Diagnostic Test

CHECK FOR AN ACTIVE DTC
NOTE:
Improperly installed aftermarket accessories can cause this DTC to set. Check for any improperly installed aftermarket accessories before continuing with this test.
1. Turn the ignition on.
2. With the scan tool, read DTCs.
  Is the DTC active?
  
  Yes
  - Go To 2
  No
  - Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
CHECK THE (F856) SECONDARY 5-VOLT SUPPLY CIRCUIT VOLTAGE
1. Turn the ignition off.
2. 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.
3. Connect the (special tool #10436, Adapter, GPEC Diagnostic).
4. Reconnect the PCM C2 harness connector with the GPEC Adaptor connected in-line with the PCM C2 harness connector.
5. Turn the ignition on.
6. Measure the voltage between ground and the (F856) Secondary 5-Volt Supply circuit at the GPEC Adaptor.
  Is the voltage between 4.9 and 5.1 volts?
  
  Yes
  - Go To 6
  No
  - Go To 3
CHECK THE SENSORS THAT SHARE THE SECONDARY 5-VOLT SUPPLY
1. IMPORTANT - FOLLOW THIS PROCEDURE EXACTLY WHEN CHECKING THE FOLLOWING COMPONENTS: Turn the ignition off before disconnecting each component. After a component has been disconnected, turn the ignition on and measure the voltage on the (F856) Secondary 5-Volt Supply circuit at the GPEC Adaptor. If the 5-Volt Supply voltage returns to 5.0 volts after disconnecting a component, the component that was disconnected is faulty. If the voltage remains low after disconnecting a component, then the disconnected component is not the problem. Leave each component disconnected and move on to the next until the faulty component is discovered or all components have been disconnected. Disconnect only one component at a time during this step.
2. Disconnect the MAP Sensor harness connector and check the Secondary 5-Volt Supply circuit voltage.
3. Disconnect the CMP Sensor harness connector and check the Secondary 5-Volt Supply circuit voltage.
4. Disconnect the APP Sensor harness connector and check the Secondary 5-Volt Supply circuit voltage.
  Were any of the above components determined to be at fault?
  
  Yes
  - Replace the faulty component in accordance with the Service Information.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 4
CHECK THE (F856) SECONDARY 5-VOLT SUPPLY CIRCUIT FOR A SHORT TO GROUND
1. Turn the ignition off.
  NOTE:
  All of the components should still be disconnected during this test step.
2. Disconnect the PCM C2 harness connector from the PCM.
3. Check for continuity between ground and the (F856) Secondary 5-Volt Supply circuit at the GPEC Adaptor.
  Is there continuity between ground and the (F856) Secondary 5-Volt Supply circuit(s)?
  
  Yes
  - Repair the (F856) Secondary 5-Volt Supply circuit for a short to ground.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 5
CHECK THE (K854) SECONDARY 5-VOLT SUPPLY CIRCUIT FOR A SHORT TO GROUND
1. Disconnect the PCM C1 harness connector.
2. Connect the (special tool #10436, Adapter, GPEC Diagnostic) to the PCM C1 harness connector.
3. Check for continuity between ground and the (K854) Secondary 5-Volt Supply circuit at the GPEC Adaptor.
  Is there continuity between ground and the (K854) Secondary 5-Volt Supply circuit(s)?
  
  Yes
  - Repair the (K854) Secondary 5-Volt Supply circuit for a short to ground.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 6
POWERTRAIN CONTROL MODULE (PCM)
1. Perform any Service Bulletins that may apply.
2. Wiggle test the engine wiring harness to test for an intermittent short while monitoring the voltage on the Secondary 5-Volt Supply circuit.
3. Look for any chafed, pierced, pinched, or partially broken wires in the engine wiring harness.
  Were 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 (PCM) in accordance with the Service Information. Refer to MODULE, POWERTRAIN CONTROL (PCM), REMOVAL .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .