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. Start the engine and allow it to idle for at least 60 seconds.
  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 a 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 FOR A SHORT TO GROUND
1. Turn the ignition off.
2. Disconnect the PCM C1 and C2 harness connectors.
3. Disconnect all the Sensors that share the (F856) Secondary 5-Volt Supply circuit.
4. Disconnect the APP Sensor harness connector.
  NOTE:
  This code can be caused by the improper installation of after market accessories that may be causing excessive noise on the (F856) 5-Volt Supply circuit.
5. Check for continuity between ground and the (F856) 5-Volt Supply circuit at the MAP Sensor harness connector.
6. Check for continuity between ground and the (K854) 5-Volt Supply circuit at the APP Sensor harness connector.
  Is there continuity between ground and the (K854) 5-Volt Supply circuit?
  
  Yes
  - Repair the (F856) 5-Volt Supply circuit for a short to ground.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 3
SENSOR SHORTED TO GROUND
1. Connect the PCM C2 harness connector and all the previously disconnected Sensors except for the MAP Sensor harness connector.
2. Turn the ignition ON.
3. Measure the voltage between ground and the (F856) Secondary 5-Volt Supply circuit in the MAP Sensor harness connector.
  NOTE:
  You must Turn the Ignition OFF when disconnecting any of the Sensor harness connectors and Turn the Ignition On to check the voltage readings.
4. While monitoring the voltage, disconnect each Sensor harness connector that shares the (F856) Secondary 5-Volt Supply circuit, one at a time including the APP Sensor harness connector.
  Does the voltage increase above 4.5 volts when disconnecting any of the Sensor harness connectors?
  
  Yes
  - Verify that there is good pin to terminal contact in the related Sensor and Powertrain Control Module harness connectors. If OK, replace the Sensor that causes the (F856) Secondary 5-Volt Supply circuit voltage to increase when disconnected.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 4
5-VOLT SENSOR
1. Turn the ignition off.
2. Connect all the previously disconnected Sensors except for the MAP Sensor harness connector.
3. Turn the ignition on.
4. Measure the voltage between ground and the (F856) Secondary 5-Volt Supply circuit in the MAP Sensor harness connector.
  Is the voltage below 4.5 volts?
  
  Yes
  - Go To 5
  No
  - Verify that there is good pin to terminal contact in the MAP Sensor and Powertrain Control Module connectors. If OK, replace the MAP Sensor. Refer to SENSOR, MANIFOLD AIR PRESSURE (MAP), REMOVAL .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK THE (F856) SECONDARY 5-VOLT SUPPLY CIRCUIT FOR A SHORT TO VOLTAGE
1. Turn the ignition off.
2. Disconnect the PCM C1 and C2 harness connectors.
3. Disconnect all the Sensors that share the (F856) Secondary 5-Volt Supply circuit.
4. Disconnect the APP Sensor harness connector.
5. Turn the ignition ON.
6. Measure the voltage between ground and the (F856) Secondary 5-Volt Supply circuit at the MAP Sensor harness connector.
  Is there any voltage present?
  
  Yes
  - Repair the short to voltage in the (F856) Secondary 5-Volt Supply circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 6
CHECK THE (F856) SECONDARY 5-VOLT SUPPLY CIRCUIT FOR AN OPEN
1. Turn the ignition off.
2. Reconnect all the sensors that were disconnected in the previous step except the MAP Sensor harness connector.
3. Measure the resistance in the (F856) Secondary 5-Volt Supply circuit from the Sensor harness connector to the PCM C2 harness connector.
4. It may be necessary to perform this test from every sensor that uses the (F856) Secondary 5-Volt Supply circuit.
  Is the resistance below 3.0 Ohms?
  
  Yes
  - Go To 7
  No
  - Repair the open in the (F856) Secondary 5-Volt Supply circuit.
  - 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 related Sensors 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 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 (PCM) in accordance with the Service Information. Refer to MODULE, POWERTRAIN CONTROL (PCM), REMOVAL .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .