Diagnostic Aids

NOTE: After each service or repair procedure has been completed, reconnect all components. Clear DTCs and repeat QUICK TEST procedures to ensure all EEC-V systems are working properly and DTCs are no longer present.

Perform this test only when directed by QUICK TEST. This test is intended to diagnose the following.

Wiring Harness Circuits (CHT & SIG RTN)
Faulty CHT Sensor
Faulty Powertrain Control Module (PCM)

NOTE: Proceed to DTC testing steps listed in FAULT CODE SETTING CONDITION table of fault code setting condition.

FAULT CODE SETTING CONDITION

Fault Code	KOEO	KOER	Continuous Memory
P0117 (Without ECT Sensor)	DL20	DL20	DL90
P0118 (Without ECT Sensor)	DL10	DL10	DL90
P0217	DL100	DL100	DL100
P1116 (Without ECT Sensor)	DL1	DL1
P1117 (Without ECT Sensor)			DL90
P1285	DL30	DL30	DL30
P1288	DL1	DL1
P1289	DL5	DL5	DL90
P1290	DL5	DL5	DL90
P1299			DL100

1) DTC P1116 Or P1288: Check CHT Sensor Operation

DTC P1116 or P1228 indicates CHT sensor is out of self-test range. Possible causes for these faults are.
- Engine Overheating
- Low Coolant Level
- Faulty Sensor
- Faulty Sensor Connector
- Poor Thermostat Operation
NOTE: If engine is a no-start or has a stalling problem, go to step 3).

Start engine and raise speed to 2000 RPM until engine is at normal operating temperature. Perform KOER ON-DEMAND SELF-TEST . Check for DTC P1116 or P1288. If DTC P1116 or P1288 is not present, engine temperature was not stabilized. Service any other DTCs and repeat QUICK TEST . If DTC P1116 or P1288 is present, go to next step.

2) Check VREF Circuit Voltage

Turn ignition switch to OFF position. Disconnect TP sensor connector. Turn ignition switch to ON position. Measure voltage between VREF and SIG RTN terminals at TP sensor harness connector. See Figure-Figure . If voltage is 4-6 volts, go to next step. If voltage is not 4-6 volts, reconnect sensor and go to TEST C .

3) Check CHT Sensor Circuit Resistance

Turn ignition switch to OFF position. Disconnect CHT sensor 2-pin connector. Measure resistance between CHT sensor terminals. See CHT SENSOR SPECIFICATIONS table. If resistance is not as specified, replace CHT sensor. If resistance is as specified and engine is a no-start or engine has a stalling concern, see SYMPTOMS in TROUBLE SHOOTING - NO CODES - EEC-V (GASOLINE) article. If resistance is as specified and engine starts and does not stall, go to next step.

CHT SENSOR SPECIFICATIONS ⁽¹⁾

Temperature °F (°C)

Volts

Ohms

-40 (-40)

4.89

965,808

-22 (-30)

4.81

513,019

-4 (-20)

4.67

283,664

14 (-10)

4.45

162,584

32 (0)

4.14

96,255

50 (10)

3.73

59,175

68 (20)

3.26

37,387

86 (30)

2.74

24,215

104 (40)

2.23

16,043

122 (50)

1.76

10,850

140 (60)

1.36

7487

158 (70)

1.04

5268

176 (80) ⁽²⁾

.79 Or 3.99

3775

185 (85) ⁽²⁾

.69 Or 3.86

3215

194 (90) ⁽²⁾

.60 Or 3.71

2750

203 (95) ⁽²⁾

.53 Or 3.56

2361

212 (100) ⁽²⁾

.46 Or 3.41

2034

230 (110)

3.07

1523

248 (120)

2.74

1155

266 (130)

2.41

.887

284 (140)

2.10

689

302 (150)

1.81

542

320 (160)

1.55

430

338 (170)

1.33

345

356 (180)

1.13

279

374 (190)

.96

228

392 (200)

.82

188

410 (210)

.70

155

428 (220)

.60

130

446 (230)

.51

109

464 (240)

.44

482 (250)

.35

500 (260)

.33

⁽¹⁾	Value may vary by 15 percent.

⁽²⁾	At this temperature, there is a voltage overlap zone due to a dual switching resistor circuit on CHT input. It is possible to have either a cold end (low voltage) or hot end (high voltage) measurement at the same temperature. Either voltage specification listed is correct.

4) Check CHT Sensor With Engine Running

Start engine. Ensure engine is at normal operating temperature. Raise engine speed to 2000 RPM for 2 minutes. Measure resistance between CHT sensor terminals. See CHT SENSOR SPECIFICATIONS table. If resistance is as specified, replace PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Program PCM. See FLASH VEHICLE IDENTIFICATION BLOCK PROCEDURE . If resistance is not as specified, replace CHT sensor.

5) DTC P1289 Or P1290

These DTCs indicate CHT sensor circuit fault. Possible causes for these faults are:
- Open Or Grounded Circuit
- Faulty Sensor
- Faulty Sensor Connector
- Faulty Powertrain Control Module (PCM)
Turn ignition switch to ON position. Using scan tool, select CHT V PID from PID/DATA MONITOR & RECORD menu. If PID voltage is less than .2 volt, go to next step. If PID voltage is .2 volt or more, go to step 7).

6) Check For Grounded Circuit

Disconnect CHT sensor 2-pin connector. Using scan tool, select CHT V PID from PID/DATA MONITOR & RECORD menu. If PID voltage is more than 4.6 volts, replace CHT sensor. If PID voltage is 4.6 volts or less, go to step 21).

7) Check For Open Circuit

Connect a jumper wire between CHT sensor harness connector terminals. Using scan tool, select CHT V PID from PID/DATA MONITOR & RECORD menu.
NOTE: If communication link error is displayed, remove jumper wire and go to step 12).

If PID voltage is less than .2 volt, replace CHT sensor. If PID voltage is .2 volt or more, remove jumper wire and go to step 11).

NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 7) to step 10). No test procedures have been omitted.

10) DTC P0118: Induce Opposite Signal To PCM

This DTC indicates CHT sensor signal is more than self-test maximum. Possible causes for this fault are:
- Open Circuit
- Faulty CHT Sensor
- Faulty PCM
Turn ignition switch to OFF position. Disconnect CHT sensor 2-pin connector. Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Connect a jumper wire between CHT sensor harness connector terminals. Turn ignition switch to ON position.

NOTE: If communication link error is displayed, remove jumper wire and go to step 12).

Using scan tool, select CHT V PID from PID/DATA MONITOR & RECORD menu. If PID voltage is less than .2 volt, replace CHT sensor. If PID voltage is .2 volt or more, remove jumper wire and go to next step.

11) Check For Open Circuit

Turn ignition switch to OFF position. Disconnect PCM connector(s). Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Measure resistance of CHT circuit between CHT sensor harness connector and PCM connector terminal C40 (LS) or terminal No. 66 (all other models). Measure resistance of SIG RTN circuit between CHT sensor harness connector and PCM connector terminal C17 (LS) or terminal No. 91 (all other models). If both resistance readings are less than 5 ohms, replace PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Program PCM. See FLASH VEHICLE IDENTIFICATION BLOCK PROCEDURE . If any resistance reading is 5 ohms or more, repair open circuit.

12) Check CHT Signal For Short To VREF

Turn ignition switch to OFF position. Disconnect PCM connector(s). Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Measure resistance between PCM harness connector CHT and VREF terminals. See WIRING DIAGRAMS article. See Figure and Figure . If resistance is more than 10 k/ohms, replace PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Program PCM. See FLASH VEHICLE IDENTIFICATION BLOCK PROCEDURE . If resistance is 10 k/ohms or less, locate and repair short circuit to VREF.
NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 12) to step 20). No test procedures have been omitted.

20) DTC P0117: Induce Opposite Signal To PCM

This DTC indicates CHT sensor signal is less than self-test minimum. Possible causes for this fault are:
- Open Or Grounded Circuit
- Faulty CHT Sensor
- Faulty PCM
Turn ignition switch to OFF position. Disconnect CHT sensor 2-pin connector. Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Turn ignition switch to ON position. Using scan tool, select CHT V PID from PID/DATA MONITOR & RECORD menu. If PID voltage is more than 4.6 volts, replace CHT sensor. If PID voltage is 4.6 volts or less, go to next step.

21) Check VREF Circuit Voltage

Disconnect TP sensor connector. Measure voltage between VREF and SIG RTN terminals at TP sensor harness connector. If voltage is 4-6 volts, reconnect TP sensor and go to next step. If voltage is not 4-6 volts, reconnect sensor and go to TEST C .

22) Check Signal Circuit For Short To Ground

Turn ignition switch to OFF position. Disconnect PCM connector(s). Inspect connector for loose, damaged or corroded terminals. Repair as necessary. On LS, measure resistance between PCM connector terminal C40 (CHT) and terminals No. A24, A25, A26, A27 (PWR GND) and C17 (SIG RTN). On all other models, measure resistance between PCM connector terminal No. 66 (CHT) and terminals No. 51 (PWR GND) and 91 (SIG RTN). If all resistance readings are more than 10 k/ohms, replace PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Program PCM. See FLASH VEHICLE IDENTIFICATION BLOCK PROCEDURE . If any resistance reading is 10 k/ohms or less, repair circuit short.
NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 22) to step 30). No test procedures have been omitted.

30) DTC P1285

This DTC indicates that PCM has sensed an engine overheat condition from CHT sensor. Check cooling system for leaks and restrictions. Check for cause of overheat condition. Repair as necessary.
NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 30) to step 40). No test procedures have been omitted.

40) Engine Temperature Warning Light Always On, Engine Is Not Overheating

If QUICK TEST was performed and no DTCs are present, go to next step. If QUICK TEST was not performed, perform QUICK TEST and service any DTCs that are present.

41) Engine Temperature Warning Light Always On (No DTCs)

This DTC indicates that PCM has sensed a engine warning light circuit fault. Possible causes for this fault are:
- Faulty Instrument Cluster
- Faulty Wiring Harness
- Faulty PCM
Disconnect PCM connector(s). Turn ignition switch to ON position. If engine temperature warning light is off and temperature gauge is reading in the normal zone, replace PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Program PCM. See FLASH VEHICLE IDENTIFICATION BLOCK PROCEDURE . If engine temperature warning light is still on, check instrument cluster and temperature warning light circuits. See appropriate INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT for diagnosis and testing.

NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 41) to step 90). No test procedures have been omitted.

90) Continuous Memory DTC P0117, P0118, P1117, P1289 Or P1290

These DTCs indicate intermittent CHT sensor failure. Possible causes for these faults are:
- Open Or Grounded Circuit
- Faulty CHT Sensor
- Low Coolant Level
- Faulty PCM
Turn ignition switch to ON position. Using scan tool, select CHT PID from PID/DATA MONITOR & RECORD menu. While observing CHT PID, lightly tap on CHT sensor to simulate road shock. Wiggle sensor connector. A fault is indicated by a sudden change of CHT PID temperature. If no fault is indicated, go to next step. If fault is indicated, turn ignition switch to OFF position. Disconnect and inspect connectors. If connectors are okay, replace CHT sensor. Clear DTCs and perform COMPREHENSIVE COMPONENT MONITOR REPAIR VERIFICATION DRIVE CYCLE. See DRIVE CYCLE PROCEDURES under ADDITIONAL SYSTEM FUNCTIONS. Repeat QUICK TEST .

91) Check Wiring Harness

Ensure CHT PID is still selected. Starting at CHT sensor connector and working toward PCM, wiggle and shake small sections of wiring harness. A fault is indicated by a sudden change of CHT PID temperature. If no fault is indicated, go to next step. If fault is indicated, isolate and repair as necessary. Clear DTCs and perform COMPREHENSIVE COMPONENT MONITOR REPAIR VERIFICATION DRIVE CYCLE. See DRIVE CYCLE PROCEDURES under ADDITIONAL SYSTEM FUNCTIONS. Repeat QUICK TEST .

92) Check PCM Wiring Harness

Turn ignition switch to OFF position. Disconnect CHT sensor and PCM connectors. Inspect connectors for loose, damaged or corroded terminals. Repair as necessary. Clear DTCs and perform COMPREHENSIVE COMPONENT MONITOR REPAIR VERIFICATION DRIVE CYCLE. See DRIVE CYCLE PROCEDURES under ADDITIONAL SYSTEM FUNCTIONS. Repeat QUICK TEST . If connectors are okay, problem cannot be located at this time. Clear DTCs and perform COMPREHENSIVE COMPONENT MONITOR REPAIR VERIFICATION DRIVE CYCLE. See DRIVE CYCLE PROCEDURES under ADDITIONAL SYSTEM FUNCTIONS. Repeat QUICK TEST.
NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 92) to step 100). No test procedures have been omitted.

100) DTC P0217 Or P1299

This DTC indicates an engine overheat condition was detected by CHT sensor and fail-safe cooling strategy was activated. Possible causes for this fault are:
- Cooling System Fault
- Low Coolant Level
- Engine Mechanical Fault
Locate cooling system fault and repair as necessary.