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.

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 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.

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.
  2. Perform POWERTRAIN VERIFICATION TEST VER - 5 .
Start the engine.
Allow the engine to reach normal operating temperature.

NOTE: If one of the O2 Sensors Signal or Return circuit is shorted to ground or voltage, all the other O2 Sensor voltage readings will be affected.

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?
1. Yes --> Go To 4
2. No --> Go To 9
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.

Ignition on, engine not running.

With the DRBIII®, perform the O2 Heater Test for each of the O2 Sensors.

With the DRBIII®, monitor all O2 Sensor voltage readings 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 DRB 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: Remove the vacuum gauge before continuing.

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 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 Engine Coolant Temperature value. The temp value change should be a smooth transition from start up to normal operating temp 82°C (180°F). The value should reach at least 82°C (180°F).

Did the ECT value increase smoothly and 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.
Disconnect the hoses at the Evap Purge Solenoid.

Using a hand vacuum pump, apply 10 inches of vacuum to the Evap Purge Solenoid vacuum source port on the component side.

Did the Evap Purge Solenoid hold vacuum?
1. Yes --> Go To 8
2. No --> Replace the EVAP Purge Solenoid.
  Perform POWERTRAIN VERIFICATION TEST VER - 5 .
NOTE: Connect the vacuum hoses before continuing.
Check for any of the following conditions/mechanical problems.
AIR INDUCTION SYSTEM - must be free from restrictions.

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 12
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 O2 Signal circuit and the O2 Return circuit in the O2 Sensor harness connector.

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

Did the O2 Sensor voltage drop from 5 volts to 2.5 volts?
1. Yes --> Replace the O2 Sensor
  Perform POWERTRAIN VERIFICATION TEST VER - 5 .
2. No --> Go To 10
NOTE: Remove the jumper wire before continuing.

WARNING: WHEN THE ENGINE IS OPERATING, DO NOT STAND IN A DIRECT LINE WITH THE FAN. DO NOT PUT YOUR HANDS NEAR THE PULLEYS, BELTS OR FAN. DO NOT WEAR LOOSE CLOTHING.

Start the engine.
Measure the voltage on the O2 Signal circuit in the O2 Sensor harness connector.

Is the voltage above 4.8 volts?
1. Yes --> Check the O2 Sensor Signal circuit for damage, 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 .
2. No --> Go To 11
Engine still running.
Measure the voltage on the O2 Return circuit in the O2 Sensor harness connector.

Is the voltage at 2.5 volts?
1. Yes --> Go To 12
2. No --> Check the O2 Sensor Return circuit for damage, 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 .
NOTE: Turn the ignition off before continuing.

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.
  2. Perform POWERTRAIN VERIFICATION TEST VER - 5 .