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
NOTE:
Diagnose any 5-Volt Supply, TPS, Cam Sensor, Crank Sensor or MAP Sensor DTCs before continuing.
1. Start the engine and allow it to idle until closed loop fueling is achieved.
2. With a scan tool, read DTCs.
  Is the DTC active or pending?
  
  Yes
  - Go To 2
  No
  - Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
COMPARE THE ENGINE VACUUM AND MAP SENSOR READING
1. Turn the engine off.
2. Connect a vacuum gauge to the Intake Manifold.
3. Start the engine and allow it to idle.
4. Monitor the reading on the vacuum gauge.
5. Monitor the MAP Sensor reading on the scan tool.
  NOTE:
  The minimum engine vacuum at idle should be no less than approximately 13.0 HG.
  
  Compare the scan tool reading to the vacuum gauge reading?
  
  Both of the readings match and are below 13.0 HG
  - Check and repair any engine vacuum leaks, exhaust restrictions, or engine mechanical conditions that can cause low engine compression.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  Engine vacuum is normal and MAP reading on scan tool does not match
  - Go To 3
CHECK FOR HIGH RESISTANCE IN THE (F856) 5-VOLT SUPPLY CIRCUIT
1. Turn the ignition off.
2. Disconnect the MAP Sensor harness connector.
3. Disconnect the PCM C2 harness connector.
  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 the GPEC Diagnostic Adaptor to perform the diagnosis.
4. Connect the (special tool #10436, Adapter, GPEC Diagnostic).
5. Measure the resistance of the (F856) 5-Volt Supply circuit between the MAP Sensor harness connector and the GPEC Adaptor.
  Is the resistance below 3.0 Ohms?
  
  Yes
  - Go To 4
  No
  - Repair the (F856) 5-Volt Supply circuit for high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK FOR HIGH RESISTANCE IN THE (K1) MAP SIGNAL CIRCUIT
1. Measure the resistance of the (K1) MAP Signal circuit between the MAP Sensor harness connector and the GPEC Adaptor.
  Is the resistance below 3.0 Ohms?
  
  Yes
  - Go To 5
  No
  - Repair the (K1) MAP Signal circuit for high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK FOR HIGH RESISTANCE IN THE (K900) SENSOR GROUND CIRCUIT
1. Measure the resistance of the (K900) Sensor Ground circuit between the MAP Sensor harness connector and the GPEC Adaptor.
  Is the resistance below 3.0 Ohms?
  
  Yes
  - Go To 6
  No
  - Repair the excessive (K900) Sensor ground circuit for high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK THE MAP SENSOR AND PORT FOR OBSTRUCTIONS
1. Remove the MAP Sensor.
2. Inspect the MAP Sensor and port for any obstructions.
  Were any obstructions found?
  
  Yes
  - Perform the appropriate repairs and retest.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 7
MAP SENSOR
1. Replace the MAP Sensor in accordance with the Service Information. Refer to SENSOR, MANIFOLD AIR PRESSURE (MAP), REMOVAL .
2. Turn the ignition on.
3. With the scan tool, erase DTCs.
4. Start the engine and allow it to idle until closed loop fueling is achieved.
5. With a scan tool, read DTCs.
  Did the DTC return?
  
  Yes
  - Go To 8
  No
  - Repair complete.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the MAP Sensor, Throttle Body, 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 MAP Sensor, Throttle Body, and Powertrain Control Module connectors.
4. Perform any Service Bulletins that may apply.
  Were there any problems found?
  
  Yes
  - Repair as necessary.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Replace and program the Powertrain Control Module in accordance with the Service Information. Refer to MODULE, POWERTRAIN CONTROL, REMOVAL and PROGRAM THE PCM (POWERTRAIN CONTROL MODULE) .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .