Diagnostics Procedures

WARNING: This page is about a different car, the 2004 Dodge Pickup and 2004 Dodge Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Refer to VERIFICATION TESTS for appropriate verification test procedures.

Diagnose all other trouble codes before continuing.
NOTE: Check for contaminants that may have damaged an O2 Sensor: contaminated fuel, unapproved silicone, oil and coolant.

Ignition on, engine not running.

With the DRBIII®, read DTCs and record the related Freeze Frame data.

Is the Good Trip Counter displayed and equal to zero?
1. Yes --> Go To 2
2. No --> Refer to the SYMPTOM: INTERMITTENT CONDITION Symptom (Diagnostic Procedure).
  Perform POWERTRAIN VERIFICATION TEST VER - 5 .

WARNING: The fuel system is under constant pressure (even with the engine off). Before testing or servicing any fuel system hose, fitting or line, the fuel system pressure must be released.

NOTE: Fuel pressure specification is 407 KPa +/- 34 KPa (59 psi +/- 5 psi).

CAUTION: Stop All Actuations.

Install a fuel pressure gauge to the fuel rail.
Ignition on, engine not running.

With the DRBIII®, actuate the ASD Fuel System test and observe the fuel pressure gauge.

Turn the ignition off.

Choose a conclusion that best matches your fuel pressure reading.
1. Within Specification
  1. Go To 3
2. Above Specification
  1. Replace the fuel filter/pressure regulator.
    Perform POWERTRAIN VERIFICATION TEST VER - 5 .
3. Below Specification
  1. Go To 12
Start the engine.
Allow the engine to reach normal operating temperature.

NOTE: If one of the O2 Sensor's Signal or Return circuit is shorted to ground the DRBIII® will display all O2 Sensor voltage readings low. The O2 Sensor that is shorted to ground will display a voltage reading near or at 0 volts.

NOTE: If one of the O2 Sensor Signal or Return circuits are shorted to voltage, the DRBIII® will display all O2 Sensor voltage readings high.

NOTE: After the repairs have been made, verify proper O2 Sensor operation. If all the O2 Sensor voltage readings have not returned to normal, follow the diagnostic procedure for the remaining O2 Sensors.

With the DRBIII®, monitor all of the O2 Sensor voltage readings.

Is the voltage switching between 2.5 and 3.4 volts for all the O2 Sensors?
1. Yes --> Go To 4
2. No --> Go To 8
Turn the ignition off.
NOTE: Wait a minimum of 10 minutes to allow the O2 Sensor to cool down before continuing the test. Allow the O2 Sensor voltage to stabilize at 5.0 volts.

NOTE: Perform the following test on all O2 Sensors.

Ignition on, engine not running.

With the DRBIII®, actuate the O2 Heater Test.

With the DRBIII®, monitor O2 Sensor voltage for at least 2 minutes.

Does the voltage stay above 4.5 volts?
1. Yes --> Replace the O2 Sensor.
  Perform POWERTRAIN VERIFICATION TEST VER - 5 .
2. No --> Go To 5
Turn the ignition off.
Connect a Vacuum Gauge to a Manifold Vacuum source.

Start the engine.

Allow the engine to idle.

NOTE: If engine will not idle, maintain a constant RPM above idle.

With the DRBIII® in Sensors, read the MAP Sensor vacuum value.

Is the DRBIII® reading within 1" of the Vacuum Gauge reading?
1. Yes --> Go To 6
2. No --> Replace the MAP Sensor.
  Perform POWERTRAIN VERIFICATION TEST VER - 5 .

NOTE: For this test to be valid, the thermostat must be operating correctly.

NOTE: This test works best if performed on a cold engine (cold soak)

NOTE: If engine coolant temperature is above 82°C (180°F), allow the engine to cool until 65°C (150°F) is reached.

Ignition on, engine not running.
With the DRBIII®, read the Engine Coolant Temperature (ECT) Sensor value. If the engine was allowed to sit overnight (cold soak), the temperature value should be a sensible value that is somewhere close to the ambient temperature.

Start the Engine.

During engine warm-up, monitor the ECT Sensor value. The temperature value change should be a smooth transition from start up to normal operating temperature 82°C (180°F). The value should reach at least 82°C (180°F).

Did the ECT value increase smoothly and did it reach at least 180°F (82°C)?
1. Yes --> Go To 7
2. No --> Replace the Engine Coolant Temperature Sensor.
  Perform POWERTRAIN VERIFICATION TEST VER - 5 .
Turn the ignition off.
Check for any of the following conditions/mechanical problems.

AIR INDUCTION SYSTEM - must be free from leaks.

ENGINE VACUUM - must be at least 13 inches in neutral

ENGINE VALVE TIMING - must be within specifications

ENGINE COMPRESSION - must be within specifications

ENGINE EXHAUST SYSTEM - must be free of any restrictions or leaks.

ENGINE PCV SYSTEM - must flow freely

TORQUE CONVERTER STALL SPEED - must be within specifications

POWER BRAKE BOOSTER - no internal vacuum leaks

FUEL - must be free of contamination

FUEL INJECTOR - plugged or restricted injector; control wire not connected to correct injector

Are there any engine mechanical problems?
1. Yes --> Repair as necessary.
  Perform POWERTRAIN VERIFICATION TEST VER - 5 .
2. No --> Go To 11
Ignition on, engine not running.
NOTE: Perform the following test on the O2 Sensors whose voltage was not switching properly in the previous step.

Disconnect the O2 Sensor harness connector.

With the DRBIII®, monitor the O2 Sensor voltage.

O2 Sensor voltage should read 5.0 volts on the DRBIII® with the connector disconnected.

Connect a jumper wire between the Signal circuit and the Return circuit in the O2 Sensor harness connector.

NOTE: The voltage should drop from 5.0 volts to 2.5 volts with the jumper wire in place.

Did the O2 Sensor voltage change from 5.0 volts to 2.5 volts?
1. Yes --> Replace the O2 Sensor.
  Perform POWERTRAIN VERIFICATION TEST VER - 5 .
2. No --> Go To 9
NOTE: Remove the jumper wire before continuing.
Only have one O2 Sensor disconnect at a time.
With the DRBIII®, monitor all the O2 Sensor voltage readings.

NOTE: The DRBIII® will display all O2 Sensor voltage readings approximately 5.0 volts when only one O2 Sensor's Signal circuit is shorted to voltage.

NOTE: The DRBIII® will display one O2 Sensor voltage close to zero and the others will read lower than normal when one O2 Sensor Signal circuit contains excessive resistance.

Is the voltage above 4.8 volts?
1. Yes --> Go To 10
2. No --> Check all the O2 Signal circuits for a short to ground, open, or short to voltage. Inspect the O2 Sensor connector and the PCM harness connector. If OK, replace and program the Powertrain Control Module per Service Information.
  Perform POWERTRAIN VERIFICATION TEST VER - 5 .
Disconnect each O2 Sensor harness connector.
Measure the voltage on the O2 Return circuits in the O2 Sensor harness connector.

NOTE: The DRBIII® will display all O2 Sensor Voltage readings approximately 5.0 volts when only one O2 Sensor's Return circuit is shorted to voltage.

NOTE: The DRBIII® will display one O2 Sensor voltage close to zero and the others will read lower than normal when one O2 Sensor Return circuit contains excessive resistance.

Is the voltage at 2.5 volts?
1. Yes --> Go To 11
2. No --> Check all the O2 Return circuits for a short to ground, open, or short to voltage. Inspect the O2 Sensor connector and the PCM harness connector. If OK, replace and program the Powertriain Control Module per Service Information.
  Perform POWERTRAIN VERIFICATION TEST VER - 5 .

NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.

Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.
If there are no possible causes remaining, view repair.
1. Repair
  1. Replace and program the Powertrain Control Module per Service Information.
    Perform POWERTRAIN VERIFICATION TEST VER - 5 .

WARNING: The fuel system is under a constant pressure (even with the engine off). Before testing or servicing any fuel system hose, fitting or line, the fuel system pressure must be released.

NOTE: Fuel pressure specification is 407 KPa +/- 34 KPa (59 psi +/- 5 psi).

CAUTION: Stop All Actuations.

Raise vehicle on hoist, and disconnect the fuel pressure line at the fuel pump module.
Install special 5/16 fuel line adapter tool #6539 between disconnected fuel line and the fuel pump module.

Attach a fuel pressure test gauge to the T fitting on tool #6539.

Ignition on, engine not running.

With the DRBIII®, actuate the ASD Fuel System test and observe the fuel pressure gauge.

Is the fuel pressure within specification?
1. Yes --> Repair or replace fuel supply line as necessary.
  Perform POWERTRAIN VERIFICATION TEST VER - 5 .
2. No --> Go To 13
Turn the ignition off.
WARNING: The fuel system is under a constant pressure (even with the engine off). Before testing or servicing any fuel system hose, fitting or line, the fuel system pressure must be released.

Remove the Fuel Pump Module and inspect the Fuel Inlet Strainer.

Is the Fuel Inlet Strainer plugged?
1. Yes --> Replace the Fuel Pump Inlet Strainer.
  Perform POWERTRAIN VERIFICATION TEST VER - 5 .
2. No --> Go To 14
If there are no possible causes remaining, view repair.
1. Repair
  1. Replace the Fuel Pump Module.
    Perform POWERTRAIN VERIFICATION TEST VER - 5 .