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.

CHECK FOR AN ACTIVE DTC
1. Turn the ignition on.
2. With the scan tool, read DTCs. Copy DTC and Freeze Frame information.
3. Start the engine and allow it to reach 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.
  
  NOTE:
  Attempt to operate the vehicle under conditions similar to which the DTC was set.
  
  NOTE:
  It may be necessary to test drive the vehicle within the DTC monitoring conditions in order for this DTC to set.
4. With the scan tool, read DTCs.
  Is the DTC active or pending?
  
  Yes
  - Go To 2
  No
  - Go To 7
CAMSHAFT POSITION SENSOR
1. Turn the ignition off.
2. Disconnect the CMP Sensor harness connector.
3. Connect a jumper wire between the (F856) 5-Volt Supply circuit and the CMP Sensor Signal circuit in the CMP Sensor harness connector.
4. Turn the ignition on.
5. With a scan tool check DTCs.
  Is the P0343-Camshaft Position Sensor Signal Circuit High DTC set?
  
  Yes
  - Verify that there is good pin to terminal contact in the CMP Sensor and Powertrain Control Module connectors. Replace the Camshaft Position Sensor if no problems were found with the connectors. Refer to SENSOR, CAMSHAFT POSITION, REMOVAL .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .
  No
  - Go To 3
CMP SIGNAL CIRCUIT SHORTED TO GROUND
1. Turn the ignition off.
2. Disconnect the PCM C2 harness connector.
3. Measure the resistance between ground and the CMP Signal circuit in the CMP Sensor harness connector.
  Is the resistance below 100 Ohms?
  
  Yes
  - Repair the short to ground in the CMP Signal circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .
  No
  - Go To 4
EXCESSIVE RESISTANCE IN THE CMP SIGNAL CIRCUIT
1. Measure the resistance of the CMP Signal circuit from the CMP Sensor harness connector to the appropriate terminal of the PCM C2 harness connector.
  Is the resistance below 3.0 Ohms?
  
  Yes
  - Go To 5
  No
  - Repair the open or excessive resistance in the CMP Signal circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .
EXCESSIVE RESISTANCE IN THE (K900) SENSOR GROUND CIRCUIT
1. Measure the resistance of the (K900) Sensor ground circuit from the CMP Sensor harness connector to the appropriate terminal of the PCM C2 harness connector.
  Is the resistance below 3.0 Ohms?
  
  Yes
  - Go To 6
  No
  - Repair open or excessive resistance in the (K900) Sensor ground circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .
POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the related Sensor 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. Verify that there is good pin to terminal contact in the related Sensor and the Powertrain Control Module harness connectors.
4. Perform any Service Bulletins that may apply.
  Were there any issues?
  
  Yes
  - Repair as necessary.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .
  No
  - Replace and program the Powertrain Control Module in accordance with the Service Information. Refer to MODULE, POWERTRAIN CONTROL, REMOVAL .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .
ERRATIC CMP SIGNAL
1. With a lab scope, back probe the CMP Signal circuit in the CMP harness connector.
  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. Turn the ignition on.
3. Wiggle the related wire harness and lightly tap the Camshaft Position Sensor.
4. Observe the lab scope screen.
5. Allow the engine to idle.
6. Observe the lab scope screen.
  Did the CMP Sensor generate any erratic pulses?
  
  Yes
  - Verify that there is good pin to terminal contact in the CMP Sensor and the Powertrain Control Module connectors. If OK, inspect the Camshaft tone wheel for irregularities. If the tone wheel is distorted replace the Camshaft in accordance with the Service Information. Refer to CAMSHAFT, ENGINE, REMOVAL . If no problems were found with the tone wheel, replace the Camshaft Position Sensor. Refer to SENSOR, CAMSHAFT POSITION, REMOVAL .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .
  No
  - Go To 8
ERRATIC CKP SIGNAL
1. Turn the ignition off.
2. With a lab scope, backprobe the (K24) CKP Signal circuit in the CKP harness connector.
  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.
3. Turn the ignition on.
4. Wiggle the related wire harness and lightly tap on the Crankshaft Position Sensor.
5. Observe the lab scope screen.
6. Allow the engine to idle.
7. Observe the lab scope screen.
  Did the CKP Sensor generate any erratic pulses?
  
  Yes
  
  SENSOR, CRANKSHAFT POSITION, REMOVAL
  - Verify that there is good pin to terminal contact in the CKP Sensor and the Powertrain Control Module connectors. If OK, replace the Crankshaft Position Sensor. Refer to SENSOR, CRANKSHAFT POSITION .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 16V Turbo .
  No
  - Test complete, the conditions that set this DTC are not present at this time. Using the wiring diagram as a guide, check all related splices and connections for signs of water intrusion, corrosion, pushed out or bent terminals and correct pin tension.