Fuel And Emissions Systems - Engine Will Not Start, Engine Starts But Stalls Immediately, Or Engine Is Hard To Start

Special Tools Required

Vacuum Pump/Gauge, 0-30 inHg Snap-on YA4000A or equivalent, commercially available

NOTE:

Before beginning this troubleshooting, ask a customer about diagnostic interview - Go to: Fuel and Emissions Systems Symptom Troubleshooting - Hard to start engine Diagnostic interview .
- When the symptom cannot be duplicated, you can do the troubleshooting using the - Go to: PGM-FI System Description - On-Board Snapshot in this procedure.
  Use the diagnostic interview (date, place) and the present total mileage, and compare the total mileage which is estimated from the interview when a failure occurred and the parameter (total mileage) in the on-board snapshot information. Make sure the date when the failure occurred corresponds with the date on which the on-board snapshot information was recorded. If it doesn't, the on-board snapshot information cannot be used in this troubleshooting.
Before beginning this troubleshooting:
- Make sure the 12 volt battery is fully charged.
- Make sure the fuel tank is at least 1/4 full.
- Make sure the engine oil level is correct.
After the troubleshooting, reset the PCM Rest (HDS - Connect) to certainly erase the on-board snapshot information recorded on the PCM.

DTC check

-1. Turn the vehicle to the ON mode.

- 2. Check for Pending or Confirmed DTCs with the HDS.

DTC Description	Confirmed DTC	Pending DTC	Freeze Frame

Are any Pending or Confirmed DTCs indicated?

YES

Go to the indicated DTC's troubleshooting.

Go to step 2.

NOTE: If the HDS does not communicate with the PGM-FI system, go to the PCM power and ground circuit troubleshooting - Refer to:

PCM Power and Ground Circuit Troubleshooting (2019 2020 2021)

PCM Power and Ground Circuit Troubleshooting (6-Speed A/T), ('16-'18 9-Speed A/T)

Immobilizer system check
-1. Check the status log of the immobilizer system. Keyless Access System Status Log

NOTE: When a status log count is found, it means the immobilizer system has kept the engine from starting in the past. The number of status log count shows how often the system has kept the engine from starting in the past. If the immobilizer system has no status log count, the system is normal.

Was the status log count found?

YES

Check for probable cause of the status log Keyless Access System Status Log .

NO

Go to step 3.
Problem verification (snapshot sampling)
-1. Set the HDS to record a SNAPSHOT of following parameters for 30 seconds.
- IMMOBILIZER
- ENGINE SPEED
- BATTERY
- ECT SENSOR 1
- MAP SENSOR
- MAF SENSOR
- FUEL PRESSURE CONVERTED FROM PF SENSOR
- FUEL PRESSURE DIRECT INJECTION SYSTEM
- CMP B NO PULSE
- CMP B NOISE
- CKP NO PULSE
- CKP NOISE
- EGR valve position sensor (EGR VLS)
- ROCKER ARM OIL PRESSURE SWITCH A
Data List

- 2. Begin the snapshot, then try to start the engine.

Is the engine hard to start?

YES

Go to step 5 (diagnosis by parameter troubleshooting).

NO

Go to step 4.
On-board snapshot check (Engine will not start)
-1. Check the record of Hard to Start Engine in the on-board snapshot with the HDS.

On-board Snapshot

Is the Hard to Start Engine in the on-board snapshot recorded?

YES

Go to step 5 (diagnosis by parameter troubleshooting).

NO

Go to step 17.

On-board snapshot or snapshot check (IMMOBILIZER):

NOTE: Use the on-board snapshot in the case of an intermittent failure, or use the snapshot in the case of a reproducible failure.

-1. Select the Hard to Start Engine in the on-board snapshot or snapshot with the HDS.

On-board Snapshot

- 2. Select the IMMOBILIZER and ENGINE SPEED in the configuration list.

Compare the snapshot parameters observed while the engine was cranking, to those in the chart below, to determine the problem.

Pattern	Symptom (Diagnosis by parameter)	Additional remarks
Pattern 1	IMMOBILIZER inhibit Courtesy of HONDA, U.S.A., INC.HONDA, U.S.A., INC. IMMOBILIZER inhibit Courtesy of HONDA, U.S.A., INC.HONDA, U.S.A., INC.	When IMMOBILIZER indicates "BAN" during cranking or after start, the fuel pump is stopped by IMMOBILIZER inhibit. No failure in the engine
Pattern 2	IMMOBILIZER permit Normal Courtesy of HONDA, U.S.A., INC.HONDA, U.S.A., INC. IMMOBILIZER permit Normal Courtesy of HONDA, U.S.A., INC.HONDA, U.S.A., INC.	IMMOBILIZER is normal when IMMOBILIZER indicates "RUN" when cranking or after start.

Which pattern is indicated?

Pattern 1

The immobilizer system has a failure. Go to the Keyless Access System Check .

Pattern 2

The immobilizer system is OK. Go to step 6 (diagnosis by parameter (ENGINE SPEED)).

On-board snapshot or snapshot check (ENGINE SPEED):

NOTE: Use the on-board snapshot in the case of an intermittent failure, or use the snapshot in the case of a reproducible failure.

-1. Select the Hard to Start Engine in the on-board snapshot or snapshot with the HDS.

On-board Snapshot

- 2. Select the ENGINE SPEED pattern chart in the configuration list.

Check the recorded snapshot parameters while the engine is cranking, then compare the pattern from the chart, and determine the problem.

Pattern	Symptom (Diagnosis by parameter)	Additional remarks
Pattern 1	ENGINE SPEED when cranking is normal Courtesy of HONDA, U.S.A., INC.
Pattern 2	ENGINE SPEED when cranking is low Courtesy of HONDA, U.S.A., INC.	When ENGINE SPEED during cranking is low, weak 12 volt battery or increased engine friction can be considered.

Which pattern is indicated?

Pattern 1

The engine cranking speed is OK. Go to step 7 (diagnosis by parameter (BATTERY)).

Pattern 2

Diagnostic procedure:

1.
Test the 12 volt battery - Refer to:

12 Volt Battery Test (Without Auto Idle Stop System) or

12 Volt Battery Test (Without Auto Idle Stop System) .
2. Check the 12 volt battery cables and the connections.
3.
Check the starter - Refer to:

Starter Removal, Installation and Performance Test (6-Speed A/T) or

Starter Removal, Installation and Performance Test .
4. Check for engine friction.

On-board snapshot or snapshot check (BATTERY):

NOTE: Use the on-board snapshot in the case of an intermittent failure, or use the snapshot in the case of a reproducible failure.

-1. Select the Hard to Start Engine in the on-board snapshot or snapshot with the HDS.

On-board Snapshot

- 2. Select the BATTERY and ENGINE SPEED in the configuration list.

Check the recorded snapshot parameters while the engine is cranking, then compare the BATTERY pattern from the chart, and determine the problem.

Pattern	Symptom (Diagnosis by parameter)	Additional remarks
Pattern 1	BATTERY voltage low when cranking Courtesy of HONDA, U.S.A., INC.	When BATTERY voltage during cranking is too low, there is a possibility that PCM and/or the engine will not start. The PCM and other system control units require 7.0 V or more to start.
Pattern 2	BATTERY voltage normal when cranking Courtesy of HONDA, U.S.A., INC.	To start the engine, 7.0 V or more is needed

Which pattern is indicated?

Pattern 1

Diagnostic procedure:

1.
Test the 12 volt battery - Refer to:

12 Volt Battery Test (Without Auto Idle Stop System) or

12 Volt Battery Test (Without Auto Idle Stop System) .
2. Check the 12 volt battery cables and the connections.

Pattern 2

The 12 volt battery is OK. Go to step 8 (diagnosis by parameter (ECT SENSOR 1)).

On-board snapshot or snapshot check (ECT SENSOR 1):

NOTE: Use the on-board snapshot in the case of an intermittent failure, or use the snapshot in the case of a reproducible failure.

-1. Select the Hard to Start Engine in the on-board snapshot or snapshot with the HDS.

On-board Snapshot

- 2. Select ECT SENSOR 1 and ENGINE SPEED in the configuration list.

Check the recorded snapshot parameters while the engine is cranking, then compare the ECT SENSOR 1 pattern from the chart, and determine the problem.

Pattern	Symptom (Diagnosis by parameter)	Additional remarks
Pattern 1	ECT SENSOR 1 high when cranking Courtesy of HONDA, U.S.A., INC.	When ECT SENSOR 1 indicates about 176 °F (80 °C) or more when the engine is cold (engine temp low), ECT sensor 1 may be stuck high. ECT compensation is not applied after the engine is warmed up, it is not necessary to check ECT sensor 1 (not a faulty part).
Pattern 2	ECT SENSOR 1 normal when cranking Courtesy of HONDA, U.S.A., INC.	If actual engine temp is nearly the same as the temp detected by ECT sensor 1 when cranking, ECT sensor 1 is normal.

Which pattern is indicated?

Pattern 1

Check for a short in the ECT sensor 1 circuit and a failure in ECT sensor 1.

Pattern 2

Go to step 9.

ECT sensor 1 check

-1. Turn the vehicle to the OFF (LOCK) mode.

- 2. Let the engine cool for 24 hours.

- 3. Measure the ambient temperature of the engine with the thermometer.

- 4. Turn the vehicle to the ON mode, but do not start the engine.

- 5. Check the parameter(s) below with the HDS.

Signal	Current conditions
Signal	Values	Unit
ECT SENSOR 1
ECT SENSOR 2

Are the values of ECT SENSOR 1, ECT SENSOR 2, and the ambient temperature almost the same?

YES

ECT sensor 1 is OK. Go to step 10 (diagnosis by parameter (MAP SENSOR)).

If the value of ECT SENSOR 1 is much higher (or lower) than that of ECT SENSOR 2, and the ambient temperature, check for the ECT sensor 1 circuit and a failure in ECT sensor 1.

On-board snapshot or snapshot check (MAP SENSOR):

NOTE: Use the on-board snapshot in the case of an intermittent failure, or use the snapshot in the case of a reproducible failure.

-1. Select the Hard to Start Engine in the on-board snapshot or snapshot with the HDS.

On-board Snapshot

- 2. Select the MAP SENSOR and ENGINE SPEED in the configuration list.

Check the recorded snapshot parameters while the engine is cranking, then compare the MAP SENSOR pattern to the pattern from the chart below, and determine the problem.

Pattern	Symptom (Diagnosis by parameter)	Additional remarks
Pattern 1	MAP SENSOR detects no change of pressure when cranking Courtesy of HONDA, U.S.A., INC.	When MAP SENSOR detects no change of pressure when cranking, the pressure measurement port may be clogged. The PCM decides basic duration time of fuel injection from engine speed and MAP sensor signal when cranking.
Pattern 2	Normal when MAP SENSOR detects vacuum when cranking Courtesy of HONDA, U.S.A., INC.	When MAP SENSOR detects vacuum while cranking, the condition is normal and the MAP sensor pressure port is clear.

Which pattern is indicated?

Pattern 1

Check the pressure measurement port of the MAP sensor for clogging, foreign objects, etc.

Pattern 2

The MAP sensor is OK. Go to step 11 (diagnosis by parameter (MAF SENSOR)).

On-board snapshot or snapshot check (MAF SENSOR):

NOTE: Use the on-board snapshot in the case of an intermittent failure, or use the snapshot in the case of a reproducible failure.

-1. Select the Hard to Start Engine in the on-board snapshot or snapshot with the HDS.

On-board Snapshot

- 2. Select the MAF SENSOR and ENGINE SPEED in the configuration list.

Check the recorded snapshot or on-board snapshot parameters while the engine is cranking, then compare the MAF SENSOR pattern from the chart, and determine the problem.

Pattern	Symptom (Diagnosis by parameter)	Additional remarks
Pattern 1	Poor connection of MAF SENSOR Courtesy of HONDA, U.S.A., INC.	Complete combustion stall: When MAF SENSOR indicates "0" 1-2 sec before ENGINE SPEED becomes 0 RPM, or when "0" is shown like noise, there may be a poor connection at the MAF sensor connector.
Pattern 2	MAF SENSOR output incorrect Courtesy of HONDA, U.S.A., INC.	When MAF SENSOR shows "0" when cranking or after start, clogging in MAF sensor's measurement port may be contaminated with debris or there may be a poor connection at its connector.

Pattern	Symptom (Diagnosis by parameter)	Additional remarks
Pattern 3	MAF SENSOR Normal Courtesy of HONDA, U.S.A., INC.	When MAF SENSOR output compares with ENGINE SPEED when cranking or after starting, the MAF sensor is normal.

Which pattern is indicated?

Pattern 1 and 2

Check for loose terminals or a poor connection at the MAF sensor.

Pattern 3

The MAF sensor/IAT sensor is OK. Go to step 12 (diagnosis by parameter (FUEL PRESSURE CONVERTED FROM PF SENSOR and FUEL PRESSURE DIRECT INJECTION SYSTEM)).

On-board snapshot or snapshot check (FUEL PRESSURE CONVERTED FROM PF SENSOR and FUEL PRESSURE DIRECT INJECTION SYSTEM):

NOTE: Use the on-board snapshot in the case of an intermittent failure, or use the snapshot in the case of a reproducible failure.

-1. Select the Hard to Start Engine in the on-board snapshot or snapshot with the HDS.

On-board Snapshot

- 2. Select the FUEL PRESSURE CONVERTED FROM PF SENSOR, the FUEL PRESSURE DIRECT INJECTION SYSTEM, and ENGINE SPEED in the configuration list.

Check the recorded snapshot or on-board snapshot parameters while the engine is cranking, then compare the FUEL PRESSURE CONVERTED FROM PF SENSOR and FUEL PRESSURE DIRECT INJECTION SYSTEM patterns from the chart, and determine the problem.

Pattern	Symptom (Diagnosis by parameter)	Additional remarks
Pattern 1	The FUEL PRESSURE CONVERTED FROM PF SENSOR is low (almost 0 kPa) when cranking Courtesy of HONDA, U.S.A., INC.	If the FUEL PRESSURE CONVERTED FROM PF SENSOR is almost 0 kPa when cranking, a failure may exist in the fuel supply system. Fuel leak, out of fuel Fuel rail pressure sensor failure Spill valve stuck off Fuel pressure regulator (low pressure side) Fuel pump (low pressure side) High pressure fuel pump
Pattern 2	Normal when the FUEL PRESSURE CONVERTED FROM PF SENSOR follows the FUEL PRESSURE DIRECT INJECTION SYSTEM when cranking Courtesy of HONDA, U.S.A., INC.	If the FUEL PRESSURE CONVERTED FROM PF SENSOR is nearly the same as the FUEL PRESSURE DIRECT INJECTION SYSTEM when cranking, the fuel pressure is normal. Fuel pressure may be low when the start of cranking.

Which pattern is indicated?

Pattern 1

Go to the troubleshooting for DTC P0087 - Refer to:

DTC Troubleshooting: P0087 or

DTC Troubleshooting: P0087 (2019 2020 2021)

Pattern 2

The fuel pressure is OK. Go to step 13 (diagnosis by parameter (CMP B NO PULSE)).

On-board snapshot or snapshot check (CMP B NO PULSE):

NOTE: Use the on-board snapshot in the case of an intermittent failure, or use the snapshot in the case of a reproducible failure.

-1. Select the Hard to Start Engine in the on-board snapshot or snapshot with the HDS.

On-board Snapshot

- 2. Select the CMP B NO PULSE and ENGINE SPEED in the configuration list.

Check the recorded snapshot parameters while the engine is cranking, then compare the CMP B NO PULSE pattern from the chart, and determine the problem.

Pattern	Symptom (Diagnosis by parameter)	Additional remarks
Pattern 1	CMP B NO PULSE count increases continuously when cranking Courtesy of HONDA, U.S.A., INC.	When CMP B NO PULSE count increases continuously when cranking, no CMP pulse is received. If the CMP pulse is not received, the PCM cannot detect the cylinder to be ignited and the engine is unable to start.
Pattern 2	The CMP B NO PULSE count does not increase continuously when cranking Courtesy of HONDA, U.S.A., INC.	It is normal when CMP B NO PULSE count does not increase continuously when cranking.

Which pattern is indicated?

Pattern 1

Go to the troubleshooting for DTC P0365 - Refer to:

DTC Troubleshooting: P0365 (2019 2020 2021) or

DTC Troubleshooting: P0365

If the CMP B NO PULSE count reaches the malfunction threshold, DTC P0365 will be set. Check for poor connections and loose terminals at the CMP sensor.

Pattern 2

Go to step 14 (diagnosis by parameter (CMP B NOISE)).

On-board snapshot or snapshot check (CMP B NOISE):

NOTE: Use the on-board snapshot in the case of an intermittent failure, or use the snapshot in the case of a reproducible failure.

-1. Select the Hard to Start Engine in the on-board snapshot or snapshot with the HDS.

On-board Snapshot

- 2. Select the CMP B NOISE and ENGINE SPEED in the configuration list.

Check the recorded snapshot parameters while the engine is cranking, then compare the CMP B NOISE pattern from the chart, and determine the problem.

Pattern	Symptom (Diagnosis by parameter)	Additional remarks
Pattern 1	CMP B NOISE count increases continuously when cranking Courtesy of HONDA, U.S.A., INC.	When CMP B NOISE count increases continuously when cranking, there is noise in the CMP signal. When CMP signal has noise, the PCM cannot detect the cylinder to be ignited and the engine is unable to start.
Pattern 2	The CMP B NOISE count does not increase continuously when cranking Courtesy of HONDA, U.S.A., INC.	It is normal when CMP B NOISE count does not increase continuously when cranking.

Which pattern is indicated?

Pattern 1

Go to the troubleshooting for DTC P0369 .

If the CMP B NOISE count reaches the malfunction threshold, DTC P0369 will be set. Check for poor connections and loose terminals at the CMP sensor.

Pattern 2

The CMP sensor is OK. Go to step 15 (diagnosis by parameter (CKP NO PULSE)).

On-board snapshot or snapshot check (CKP NO PULSE):

NOTE: Use the on-board snapshot in the case of an intermittent failure, or use the snapshot in the case of a reproducible failure.

-1. Select the Hard to Start Engine in the on-board snapshot or snapshot with the HDS.

On-board Snapshot

- 2. Select the CKP NO PULSE and ENGINE SPEED in the configuration list.

Check the recorded snapshot parameters while the engine is cranking, then compare the CKP NO PULSE pattern from the chart, and determine the problem.

Pattern	Symptom (Diagnosis by parameter)	Additional remarks
Pattern 1	CKP NO PULSE count increases continuously when cranking Courtesy of HONDA, U.S.A., INC.	When the CKP NO PULSE count increases continuously when cranking, the PCM is not receiving the correct CKP pulse.
Pattern 2	The CKP NO PULSE count does not increase continuously when cranking Courtesy of HONDA, U.S.A., INC.	It is normal when the CKP NO PULSE count does not increase continuously when cranking.

Which pattern is indicated?

Pattern 1

Go to the troubleshooting for DTC P0335 - Refer to:

DTC Troubleshooting: P0335, or

DTC Troubleshooting: P0335 (2019 2020 2021)

If the CKP NO PULSE count reaches the malfunction threshold, DTC P0335 will be set. Check for poor connections and loose terminals at the CKP sensor.

Pattern 2

Go to step 16 (diagnosis by parameter (CKP NOISE)).

On-board snapshot or snapshot check (CKP NOISE):

NOTE: Use the on-board snapshot in the case of an intermittent failure, or use the snapshot in the case of a reproducible failure.

-1. Select the Hard to Start Engine in the on-board snapshot or snapshot with the HDS.

On-board Snapshot

- 2. Select the CKP NOISE and ENGINE SPEED in the configuration list.

Check the recorded snapshot parameters while the engine is cranking, then compare the CKP NOISE pattern from the chart, and determine the problem.

Pattern	Symptom (Diagnosis by parameter)	Additional remarks
Pattern 1	CKP NOISE count increases continuously when cranking Courtesy of HONDA, U.S.A., INC.	When the CKP NOISE count increases continuously when cranking, the PCM is not receiving the correct CKP pulse.
Pattern 2	The CKP NOISE count does not increase continuously when cranking Courtesy of HONDA, U.S.A., INC.	It is normal when CKP NOISE count does not increase continuously when cranking.

Which pattern is indicated?

Pattern 1

Go to the troubleshooting for DTC P0339 .

If the CKP NOISE count reaches the malfunction threshold, DTC P0339 will be set. Check for poor connections and loose terminals at the CKP sensor, and also check for aftermarket accessories.

Pattern 2

The CKP sensor is OK. Go to step 17 (fuel system troubleshooting).

Fuel pressure check
-1. Do the fuel pressure test. Fuel Pressure Test

Is the fuel pressure OK?

YES

Go to step 18 (ignition system troubleshooting).

NO

Check the following parts:
- Go to the fuel pump circuit troubleshooting - Refer to:
  Fuel Pump Circuit Troubleshooting (6-Speed A/T), ('16-'18 9-Speed A/T) or
  
  Fuel Pump Circuit Troubleshooting (2019 2020 2021) .
- Fuel Pressure Regulator
- Fuel Filter
Spark plug visual check
-1. Turn the vehicle to the OFF (LOCK) mode.

- 2. Remove the spark plugs. Ignition Coil and Spark Plug - Removal and Installation .

- 3. Check the condition of the spark plug electrodes.

NOTE: Make sure the spark plugs have the correct part number for the vehicle. If the plugs are aftermarket's products or they do not have the correct part number, replace all of the plugs and retest.

Is the electrode damage or wet?
1. YES (wet)
  
  Check the following conditions. If those conditions do not apply, go to step 19.
  - In very cold conditions, multiple very short trips can cause the spark plug to foul. If this is the case, drive the vehicle a longer distance and recheck.
  - Incorrect or poor quality fuel can cause a wet spark plug. Replace the fuel and recheck.
  YES (damaged)
  
  Replace the damaged Ignition Coil and Spark Plug - Removal and Installation , determine the cause of the spark plug damage.
  
  NO
  
  Go to step 19.
Determine possible failure area (ignition system, others)
-1. Turn the vehicle to the OFF (LOCK) mode.

- 2. Fit a spark plug to the ignition coil and ground it to the engine.

- 3. Turn the vehicle to the ON mode.

- 4. Select the ALL INJECTORS in the INSPECTION MENU with the HDS, and stop fuel injection operation.

ALL INJECTORS

Crank the engine and watch for spark at the spark plug.

Does the spark plug sparkΩ

YES

The ignition system is OK. Select PCM reset in the PGM-FI INSPECTION MENU to cancel ALL INJECTORS STOP with the HDS, then go to step 21 (engine compression troubleshooting).

NO

Go to step 20.

Ignition coil power circuit check

-1. Disconnect the following connector(s).

Ignition coil(s) 3P connector from the problem cylinder

- 2. Turn the vehicle to the ON mode.

- 3. Measure the voltage between test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
Test condition	Ignition coil 3P connector: disconnected
Test point 1	Ignition coil 3P connector No. 1
Test point 2	Ignition coil 3P connector No. 2

Courtesy of HONDA, U.S.A., INC.

Is there battery voltage?

YES

Replace the Ignition Coil and Spark Plug - Removal and Installation .

Repair an open in the IG COIL/IG(IGN COIL J/C)/IG(IGN COIL) wire between the relay circuit board and the ignition coil.

Engine compression check
-1. Do an engine compression inspection. Engine Compression Inspection

Is engine compression OK?

YES

Go to step 22 (EVAP canister purge valve check).

NO

Check for wear or damage to these parts:
- Incorrect valve clearance
- Confirmation of cam timing
- Oil pressure relief valve
- Damage or worn cam lobes
- Damage or worn valve and seats
- Damage cylinder head gasket
- Damage or worn piston rings
- Damage or worn piston and cylinder bore
EVAP canister purge valve check
-1. Turn the vehicle to the OFF (LOCK) mode.

- 2. Disconnect the following connector.

EVAP canister purge valve 2P connector

- 3. Disconnect the vacuum hose (A) from the EVAP canister purge valve (B) in the engine compartment, and connect the vacuum pump/gauge, 0 - 30 inHg, to the EVAP canister purge valve.

Courtesy of HONDA, U.S.A., INC.

- 4. Start the engine.

Does the vacuum gauge indicate vacuum?

YES

Replace the EVAP Canister Purge Valve - Removal and Installation .

NO (Reproducible failure)

Go to step 23 (fuse check).

NO (Intermittent failure)

Go to step 24 (relay check).

Fuse check

-1. Check the following fuses.

Fuse	No. A12 (20 A) to the injector relay
	No. A22 (15 A) to the relay circuit board (PGM-FI subrelay circuit)
	No. A23 (15 A) to the relay circuit board (ignition coil relay circuit)
	No. A21 (15 A) to the relay circuit board (PGM-FI main relay 1 circuit)
Location	Under-hood fuse/relay box

Fuse	No. C6 (20 A) to PGM-FI main relay 2
Location	Under-dash fuse/relay box

Are the fuses OK?

YES

The fuses are OK. Go to step 24 (relay check).

Replace the blown fuse(s).

Relay check
-1. Test the following relays:

NOTE: In situations where the failure is difficult to reproduce, the following relays may have an intermittent failure.
- Relay circuit board (includes PGM-FI main relay 1 circuit, ignition coil relay circuit, and PGM-FI subrelay circuit)
- PGM-FI main relay 2 - Refer to:
  Power Relay Test (2016 2017 2018) or
  
  Power Relay Test (2019 2020 2021) .
- Injector relay - Refer to:
  Power Relay Test (2016 2017 2018) or
  
  Power Relay Test (2019 2020 2021) .
Are the relay circuit board and the relays OK?

YES

Go to step 25 (power and ground terminal check).

NO

Replace any damaged relays.
Power and ground terminal check
-1. Check the corrosion and looseness at the following terminals:
- 12 volt battery terminals
- Ground cable terminals between the engine and the body ground, and the transmission and the body ground
- Engine wire harness ground (G101)
Are the terminals OK?

YES

Go to step 26 (connector terminal check).

NO

Repair any terminal(s) as needed.
Connector terminal check
-1. Check the foreign objects clogged and corrosion at the following connector terminals:
- PCM connectors - Refer to:
  PCM Connector for Inputs and Outputs (6-Speed A/T) (2016 2017 2018 2019 2020) or
  
  PCM Connector for Inputs and Outputs (2016 2017 2018) or
  
  PCM Connector for Inputs and Outputs (2019 2020 2021)
- - IGP, M RLY
  - IG1M, DBW RLY
  - IG1 FUEL PUMP, IMOFLR
  - INJ RLY
  - GND1, GND2 LG, GND3, PGM
  - INJ Ti 1, INJ Ti 2, INJ Ti 3, INJ Ti 4, INJ Ti 5, INJ Ti 6, INJF1, INJF2, INJF3, FPF, HPTI
  - IGN PULSE1, IGN PULSE2, IGN PULSE3, IGN PULSE4, IGN PULSE5, IGN PULSE6
  - TDC
  - CRK
  - PB
  - VGP, VGM
  - TW
  - PCS
  - E EGR, EGRL
  - MTR1, MTR2, THL1, THL2
- CMP sensor
- CKP sensor
- Ignition coils
- Injectors
- Injector control module
- High pressure fuel pump
- ECT sensor
- MAF sensor
- MAP sensor
- EGR valve
- Throttle body
- EVAP canister purge valve
- Fuel tank unit
Are the terminals OK?

YES

Go to the diagnostic interview for hard to start engine - Go to: Fuel and Emissions Systems Symptom Troubleshooting - Hard to start engine Diagnostic interview .

NO

Repair any terminal(s) as needed.