Diagnostic Test

WARNING: This page is about a different car, the 2009 Dodge Caliber. However, it is still accessible from the selected car via links, so may be relevant.

DTC IS ACTIVE
NOTE: Diagnose and repair any system voltage or sensor reference voltage DTCs before continuing with this test.
1. Start the engine and allow it to reach normal operating temperature.
  WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not wear loose clothing. Failure to follow these instructions may result in possible serious or fatal injury.
2. With the scan tool, select View DTCs.
  Is the status Active for this DTC?
  
  Yes
  - Go to step 2
  No
  - Refer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure
(C818) A/C PRESSURE SENSOR SUPPLY CIRCUIT SHORTED TO VOLTAGE

Fig 1: Checking A/C Pressure Sensor Circuit
Courtesy of CHRYSLER LLC
1. Turn the ignition off.
2. Disconnect the A/C Pressure Transducer connector.
3. Disconnect the Totally Integrated Power Module (TIPM) connector.
4. Turn the ignition on.
5. Measure the voltage of the (C818) A/C Pressure Sensor Supply circuit in the A/C Pressure Transducer harness connector.
  Is there any voltage present?
  
  Yes
  - Repair the (C818) A/C Pressure Sensor Supply circuit for a short to voltage.
  - Perform the PCM Verification Test. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
  No
  - Go to step 3
(C18) A/C PRESSURE SENSOR SIGNAL CIRCUIT SHORTED TO VOLTAGE

Fig 2: Checking A/C Pressure Sensor Circuit
Courtesy of CHRYSLER LLC
1. Measure the voltage of the (C18) A/C Pressure Sensor Signal circuit in the A/C Pressure Transducer harness connector.
  Is there any voltage present?
  
  Yes
  - Repair the (C18) A/C Pressure Sensor Signal circuit for a short to voltage.
  - Perform the PCM Verification Test. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
  No
  - Go to step 4
(C18) A/C PRESSURE SENSOR SIGNAL CIRCUIT SHORTED TO THE (C818) A/C PRESSURE SENSOR SUPPLY CIRCUIT

Fig 3: Checking A/C Pressure Sensor Circuit
Courtesy of CHRYSLER LLC
1. Measure the resistance between the (C18) A/C Pressure Sensor Signal circuit and the (C818) A/C Pressure Sensor Supply circuit in the A/C Pressure Transducer harness connector.
  Is the resistance below 100 ohms?
  
  Yes
  - Repair the (C18) A/C Pressure Sensor Signal circuit for a short to the (C818) A/C Pressure Sensor Supply circuit.
  - Perform the PCM Verification Test. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
  No
  - Go to step 5
(C18) A/C PRESSURE SENSOR SIGNAL CIRCUIT OPEN OR HIGH RESISTANCE

Fig 4: Checking A/C Pressure Sensor Circuit
Courtesy of CHRYSLER LLC
1. Turn the ignition off.
2. Measure the resistance of the (C18) A/C Pressure Sensor Signal circuit between the A/C Pressure Transducer harness connector and the Totally Integrated Power Module (TIPM) harness connector.
  Is the resistance below 5.0 ohms?
  
  Yes
  - Go to step 6
  No
  - Repair the (C18) A/C Pressure Sensor Signal circuit for an open circuit or high resistance.
  - Perform the PCM Verification Test. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
(C918) A/C PRESSURE SENSOR GROUND CIRCUIT OPEN OR HIGH RESISTANCE

Fig 5: Checking A/C Pressure Sensor Circuit
Courtesy of CHRYSLER LLC
1. Measure the resistance of the (C918) A/C Pressure Sensor Ground circuit between the A/C Pressure Transducer harness connector and the Totally Integrated Power Module (TIPM) harness connector.
  Is the resistance below 5.0 ohms?
  
  Yes
  - Go to step 7
  No
  - Repair the (C918) A/C Pressure Sensor Ground circuit for an open circuit or high resistance.
  - Perform the PCM Verification Test. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
A/C PRESSURE TRANSDUCER

Fig 6: Checking A/C Pressure Sensor Circuit
Courtesy of CHRYSLER LLC
1. Turn the ignition off.
2. Connect the Totally Integrated Power Module (TIPM) connector.
3. Connect a jumper wire between the (C918) A/C Pressure Sensor Ground circuit and the (C18) A/C Pressure Sensor Signal circuit in the A/C Pressure Transducer harness connector.
4. Turn the ignition on.
5. With the scan tool, read the A/C Pressure Transducer signal voltage.
  Is the voltage below 1.0 volt with the jumper wire in place?
  
  Yes
  - Replace the A/C Pressure Transducer in accordance with the Service Information.
  - Perform the PCM Verification Test. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
  No
  - Go to step 8
TOTALLY INTEGRATED POWER MODULE (TIPM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the A/C Pressure Transducer and the Totally Integrated Power Module (TIPM).
2. Look for any chafed, pierced, pinched, or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals.
4. Refer to any Technical Service Bulletins that may apply.
  Were any problems found?
  
  Yes
  - Repair as necessary.
  - Perform the PCM Verification Test. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
  No
  - Replace and program the Totally Integrated Power Module (TIPM) in accordance with the Service Information.
  - Perform the PCM Verification Test. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .