Diagnostic Procedure

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: Ensure the A/C refrigerant System is properly charged per Service Information.

Start the engine.
With the DRBIII®, read the A/C Pressure Sensor voltage.

Is the voltage above 4.6 volts?
1. Yes --> Go To 2
2. No --> Refer to the SYMPTOM: INTERMITTENT CONDITION Symptom (Diagnostic Procedure).
  Perform (NGC) POWERTRAIN VERIFICATION TEST VER - 2 .
Turn the ignition off.
Disconnect the A/C Pressure Sensor harness connector.

Connect a jumper wire between the (C918) A/C Pressure Signal circuit and the (K900) Sensor ground circuit at the Sensor harness connector.

Ignition on, engine not running.

With the DRBIII®, monitor the A/C Pressure Sensor voltage.

Is the voltage below 1.0 volt?
1. Yes --> Replace the A/C Pressure Sensor.
  Perform (NGC) POWERTRAIN VERIFICATION TEST VER - 2 .
2. No --> Go To 3
NOTE: Remove the jumper wire before continuing.
Turn the ignition off.
Disconnect the PCM harness connectors.

Ignition on, engine not running.

Using a 12-volt test light connected to ground, probe the (C918) A/C Pressure Signal circuit at the A/C Pressure Sensor harness connector.

Does the test light illuminate?
1. Yes --> Repair the short to battery voltage in the (C918) A/C Pressure Signal circuit.
  Perform (NGC) POWERTRAIN VERIFICATION TEST VER - 2 .
2. No --> Go To 4
Turn the ignition off.
CAUTION: DO NOT PROBE THE PCM HARNESS CONNECTORS. PROBING THE PCM HARNESS CONNECTORS WILL DAMAGE THE PCM TERMINALS RESULTING IN POOR TERMINAL TO PIN CONNECTION. INSTALL MILLER SPECIAL TOOL #8815 TO PERFORM DIAGNOSIS.

Measure the resistance of the (C918) A/C Pressure Signal circuit from the A/C Pressure Sensor harness connector to the appropriate terminal of special tool #8815.

Is the resistance below 5.0 ohms?
1. Yes --> Go To 5
2. No --> Repair the open in the (C918) A/C Pressure Signal circuit.
  Perform (NGC) POWERTRAIN VERIFICATION TEST VER - 2 .
Measure the resistance between the (C918) A/C Pressure Signal circuit and the (F855) 5-volt Supply circuit in the A/C Pressure Sensor harness connector.
Is the resistance below 5.0 ohms?
1. Yes --> Repair the short between the (F855) 5-volt Supply circuit and the (C918) A/C Pressure Signal circuit.
  Perform (NGC) POWERTRAIN VERIFICATION TEST VER - 2 .
2. No --> Go To 6

CAUTION: DO NOT PROBE THE PCM HARNESS CONNECTORS. PROBING THE PCM HARNESS CONNECTORS WILL DAMAGE THE PCM TERMINALS RESULTING IN POOR TERMINAL TO PIN CONNECTION. INSTALL MILLER SPECIAL TOOL #8815 TO PERFORM DIAGNOSIS.

Measure the resistance of the (K900) Sensor ground circuit from the A/C Pressure Sensor harness connector to the appropriate terminal of special tool #8815.
Is the resistance below 5.0 ohms?
1. Yes --> Go To 7
2. No --> Repair the open in the (K900) Sensor ground circuit
  Perform (NGC) POWERTRAIN VERIFICATION TEST VER - 2 .

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 (NGC) POWERTRAIN VERIFICATION TEST VER - 2 .