Diagnostic Test

WARNING: This page is about a different car, the 2015 Fiat 500. However, it is still accessible from the selected car via links, so may be relevant.

ACTIVE DTC
NOTE:
Diagnose and repair any system voltage or 5-Volt reference DTCs before continuing with this test.

NOTE:
Make sure the A/C refrigerant System is properly charged in accordance with the service information. Refer to SPECIFICATIONS .
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 can result in possible serious or fatal injury.
2. With the scan tool, select View DTCs.
  Is the DTC Active at this time?
  
  Yes
  - Go To 2
  No
  - Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
CHECK THE (C818) 5-VOLT SUPPLY CIRCUIT FOR A SHORT TO VOLTAGE
1. Turn the ignition off.
2. Disconnect the A/C Pressure Transducer harness connector.
3. Turn the ignition on.
4. Measure the voltage of the (C818) 5-Volt Supply circuit in the A/C Pressure Transducer harness connector.
  Does the voltage measure above 5.2 volts?
  
  Yes
  - Repair the (C818) 5-Volt Supply circuit for a short to voltage.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .
  No
  - Go To 3
CHECK THE (C18) A/C PRESSURE SENSOR SIGNAL CIRCUIT FOR A SHORT TO VOLTAGE
1. Measure the voltage of the (C18) A/C Pressure Sensor Signal circuit at the A/C Pressure Transducer harness connector.
  Does the voltage measure above 5.2 volts?
  
  Yes
  - Repair the (C18) A/C Pressure Sensor Signal circuit for a short to voltage.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .
  No
  - Go To 4
CHECK FOR THE (C18) A/C PRESSURE SENSOR SIGNAL CIRCUIT SHORTED TO THE (C818) 5-VOLT SUPPLY CIRCUIT
1. Measure the resistance between the (C18) A/C Pressure Sensor Signal circuit and the (C818) 5-Volt Supply circuit in the A/C Pressure Transducer harness connector.
  Is the resistance above 10k Ohms?
  
  Yes
  - Go To 5
  No
  - Repair the short between the (C18) A/C Pressure Sensor Signal circuit and the (C818) 5-Volt Supply circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .
CHECK THE (K914) SENSOR GROUND CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1. Turn the ignition off.
2. Disconnect the PCM C1 harness connector.
3. Measure the resistance of the (K914) Sensor Ground circuit between the A/C Pressure Transducer harness connector and the PCM C1 harness connector.
  Is the resistance below 5.0 Ohms?
  
  Yes
  - Go To 6
  No
  - Repair the (K914) Sensor Ground circuit for an open circuit or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .
A/C PRESSURE TRANSDUCER
1. Reconnect the PCM C1 harness connector.
2. Connect a jumper between the (K914) Sensor Ground circuit and the (C18) A/C Pressure Sensor Signal circuit at the A/C Pressure Transducer harness connector.
3. Turn the ignition on.
4. With the scan tool, read the A/C Pressure Transducer signal voltage.
  Is the voltage near zero volts with the jumper in place?
  
  Yes
  - Replace the A/C Pressure Transducer in accordance with the service information. Refer to TRANSDUCER, A/C PRESSURE, REMOVAL .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .
  No
  - Go To 7
POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the A/C Pressure Transducer and the Powertrain Control Module (PCM).
2. Look for any chafed, pierced, pinched or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals.
4. Perform any Technical Service Bulletins that may apply.
  Were any problems found?
  
  Yes
  - Repair as necessary.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .
  No
  - Replace and program the Powertrain Control Module (PCM) in accordance with the service information. Refer to MODULE, POWERTRAIN CONTROL, REMOVAL .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .