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 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. Turn the ignition on.
4. Measure the voltage of the (C818) A/C Pressure Sensor Supply circuit in the A/C Pressure Transducer harness connector.
  Is the voltage above 4.5 volts?
  
  Yes
  - Go to step 6
  No
  - Go to step 3
(C818) A/C PRESSURE SENSOR SUPPLY CIRCUIT SHORTED TO GROUND

Fig 2: Checking A/C Pressure Sensor Circuit
Courtesy of CHRYSLER LLC
1. Turn the ignition on.
2. Disconnect the Totally Integrated Power Module (TIPM) connector.
3. Measure the resistance between ground and the (C818) A/C Pressure Sensor Supply circuit in the A/C Pressure Transducer harness connector.
  Is the resistance above 1000 ohms?
  
  Yes
  - Go to step 4
  No
  - Repair the (C818) A/C Pressure Sensor Supply circuit for a short to ground.
  - Perform the PCM Verification Test. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
(C818) A/C PRESSURE SENSOR SUPPLY CIRCUIT SHORTED TO (C918) A/C PRESSURE SENSOR GROUND CIRCUIT

Fig 3: Checking A/C Pressure Sensor Circuit
Courtesy of CHRYSLER LLC
1. Measure the resistance between the (C818) A/C Pressure Sensor Supply circuit and the (C918) A/C Pressure Sensor Ground circuit in the A/C Pressure Transducer harness connector.
  Is the resistance above 100 ohms?
  
  Yes
  - Go to step 5
  No
  - Repair the (C818) A/C Pressure Sensor Supply circuit for a short to the (C918) A/C Pressure Sensor Ground circuit.
  - Perform the PCM Verification Test. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
(C818) A/C PRESSURE SENSOR SUPPLY CIRCUIT OPEN OR HIGH RESISTANCE

Fig 4: Checking A/C Pressure Sensor Circuit
Courtesy of CHRYSLER LLC
1. Measure the resistance of the (C818) A/C Pressure Sensor Supply 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 10
  No
  - Repair the (C818) A/C Pressure Sensor Supply circuit for an open circuit or high resistance.
  - Perform the PCM Verification Test. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
(C18) A/C PRESSURE SENSOR SIGNAL CIRCUIT SHORTED TO GROUND

Fig 5: Checking A/C Pressure Sensor Circuit
Courtesy of CHRYSLER LLC
1. Turn the ignition off.
2. Disconnect the Totally Integrated Power Module (TIPM) connector.
3. Measure the resistance between ground and the (C18) A/C Pressure Sensor Signal circuit in the A/C Pressure Transducer harness connector.
  Is the resistance above 100 ohms?
  
  Yes
  - Go to step 7
  No
  - Repair the (C18) A/C Pressure Sensor Signal circuit for a short to ground.
  - Perform the PCM Verification Test. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
(C18) A/C PRESSURE SENSOR SIGNAL CIRCUIT SHORTED TO (C918) A/C PRESSURE SENSOR GROUND CIRCUIT

Fig 6: 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 (C918) A/C Pressure Sensor Ground circuit in the A/C Pressure Transducer harness connector.
  Is the resistance above 100 ohms?
  
  Yes
  - Go to step 8
  No
  - Repair the (C18) A/C Pressure Sensor Signal circuit for a short to the (C918) A/C Pressure Sensor Ground circuit.
  - Perform the PCM Verification Test. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
(C18) A/C PRESSURE SENSOR SIGNAL CIRCUIT OPEN OR HIGH RESISTANCE

Fig 7: Checking A/C Pressure Sensor Circuit
Courtesy of CHRYSLER LLC
1. 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 9
  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 .
AC PRESSURE TRANSDUCER

Fig 8: 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 (C818) A/C Pressure Sensor Supply 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 AC Pressure Transducer signal voltage.
  Is the voltage above 4.5 volts 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 10
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 .