Diagnostic Test
- READ AND RECORD DTCS AND ENVIRONMENTAL DATA - ERASE DTCS AND CHECK FOR THE DTC TO RETURN
- With the scan tool, read DTCs in all Electronic Control Units (ECUs) and record on the repair order.
- For future reference, with the scan tool, run and save a vehicle Scan Report and all related recorded data.
- With the scan tool, erase all DTCs.
- Turn the ignition off for a minimum of 10.0 seconds.
- Turn the ignition on.
- Using the When Monitored and Set Conditions above and recorded data, operate the vehicle in the conditions that set the DTC.
- With the scan tool, read DTCs.
Did the DTC return?
Yes
- Go To 2
No
- Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
- CHECK FOR OTHER DTCS
- Refer to the recorded DTCs.
Are there any 5-Volt Reference High or Low DTCs active or pending?
Yes
- Perform the applicable diagnostic procedure(s). Refer to DIAGNOSTIC CODE INDEX .
No
- Go To 3
- Refer to the recorded DTCs.
- CHECK THE (F856) 5-VOLT SUPPLY CIRCUIT FOR PROPER VOLTAGE AT THE MAP SENSOR HARNESS CONNECTOR
- Turn the ignition off.
- Disconnect the harness connector at the component of the circuit being tested. Note: The ECU harness connector should still be connected during this test step.
- Turn the ignition on.
- Set the DVOM to measure DC voltage.
- Connect the negative lead of the DVOM to a known good ground.
- Connect the leads of the DVOM to the circuit being tested.NOTE:
Normal operating voltage should be between 4.8 and 5.2 volts.
Does the circuit have the proper voltage present?
Yes
- Go To 6
No
- Go To 4
- ISOLATE AND CHECK THE (F856) 5-VOLT SUPPLY CIRCUIT FOR AN OPEN/HIGH RESISTANCE
- The ignition must be off when checking the continuity of a circuit.
- Isolate the circuit by disconnecting the Electronic Control Unit (ECU) and the component harness connector containing the circuit being tested. Note: Use the wiring diagram as a guide to follow the path of the circuit.
- Before measuring the resistance of any circuit, first measure the resistance between the two leads of the DVOM. Note: The meter leads can add resistance to the measurement value.
- Connect the leads of the DVOM to the circuit being tested.
Is the resistance below 3.0 Ohms?
Yes
- Go To 5
No
- Repair the circuit for an open or high resistance.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
- ISOLATE AND CHECK THE (F856) 5-VOLT SUPPLY CIRCUIT FOR A SHORT TO GROUND
- The ignition must be off when checking a circuit for continuity to ground.
- Isolate the circuit by disconnecting the Electronic Control Unit (ECU) and every component harness connector containing the circuit being tested. Note: Use the wiring diagram as a guide to follow the path of the circuit.
- Connect the negative lead of the DVOM to a known good ground.
- With the positive lead of the DVOM, probe the circuit being tested at the component harness connector and check for continuity between the circuit and ground.NOTE:
There should be no continuity between ground and the circuit being tested.
Is there continuity between ground and the circuit being tested?
Yes
- Repair the circuit for a short to ground. Use the wiring diagram as a guide to trace the circuit and look for any in-line connectors to help isolate the location of the short.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
No
- Go To 9
- ISOLATE AND CHECK THE MAP SENSOR (K1) PRESSURE SIGNAL CIRCUIT FOR A SHORT TO GROUND
- The ignition must be off when checking a circuit for continuity to ground.
- Isolate the circuit by disconnecting the Electronic Control Unit (ECU) and every component harness connector containing the circuit being tested. Note: Use the wiring diagram as a guide to follow the path of the circuit.
- Connect the negative lead of the DVOM to a known good ground.
- With the positive lead of the DVOM, probe the circuit being tested at the component harness connector and check for continuity between the circuit and ground.NOTE:
There should be no continuity between ground and the circuit being tested.
Is there continuity between ground and the circuit being tested?
Yes
- Repair the circuit for a short to ground. Use the wiring diagram as a guide to trace the circuit and look for any in-line connectors to help isolate the location of the short.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
No
- Go To 7
- ISOLATE AND CHECK THE MAP SENSOR (K1) PRESSURE SIGNAL CIRCUIT FOR A SHORT TO THE (K914) SENSOR GROUND CIRCUIT
- The ignition must be off when checking for a short between circuits.
- Isolate the circuit by disconnecting the Electronic Control Unit (ECU) and every component harness connector containing the circuit being tested. Note: Use the wiring diagram as a guide to follow the path of the circuit.
- Connect the test leads of the DVOM and check for continuity between the circuits being tested at the component harness connector.NOTE:
There should be no continuity between the circuits being tested.
Is there continuity between the circuits?
Yes
- Repair the short between the circuits.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
No
- Go To 8
- CONNECT A FUSED JUMPER BETWEEN THE MAP SENSOR (K1) PRESSURE SIGNAL CIRCUIT AND THE (F856) 5-VOLT SUPPLY CIRCUIT AT THE MAP SENSOR HARNESS CONNECTOR - VERIFY ABILITY OF THE PCM TO DETECT THE SENSOR SIGNAL CIRCUIT HIGH DTC
- The Electronic Control Module (ECU) harness connectors must be connected to the ECU during this test step.
- Disconnect the sensor harness connector.
- With the ignition in the off position, connect a fused jumper between the sensor signal circuit and the 5-Volt Supply circuit at the sensor harness connector.
- Turn the ignition on.
- With the scan tool, read DTCs.
Does the scan tool display the SENSOR SIGNAL CIRCUIT HIGH DTC with the jumper in place?
Yes
- Replace the faulty sensor in accordance with the Service Information. Refer to MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR .
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
No
- Go To 9
- CHECK RELATED HARNESS CONNECTIONS
- Disconnect all PCM harness connectors.
- Disconnect all related in-line harness connections (if equipped).
- Disconnect the related component harness connectors.
- Inspect harness connectors, component connectors, and all male and female terminals for the following conditions:
- Proper connector installation.
- Damaged connector locks.
- Corrosion.
- Other signs of water intrusion.
- Weather seal damage (if equipped).
- Bent terminals.
- Overheating due to a poor connection (terminal may be discolored due to excessive current draw).
- Terminals that have been pushed back into the connector cavity.
- Check for spread terminals and verify proper terminal tension.
Repair any conditions that are found.
- Connect all PCM harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
- Connect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
- Connect all related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
- With the scan tool, erase DTCs.
- Test drive or operate the vehicle in accordance with the when monitored and set conditions.
- With the scan tool, read DTCs.
Did the DTC return?
Yes
- Replace and program the Powertrain Control Module (PCM) in accordance with the Service Information. Refer to MODULE, POWERTRAIN CONTROL (PCM), REMOVAL AND INSTALLATION .
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
No
- Repair the poor connections.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .