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 (ECU's) and record on the repair order.
- With the scan tool, run a vehicle Scan Report, or record the Environmental Data related to the DTCs.
- With the scan tool, erase all DTCs.
- Turn the ignition off for a minimum of 10.0 seconds.
- Turn the ignition on.
- Using the recorded Environmental Data and the When Monitored Conditions above, operate the vehicle in the conditions that set the DTC.
- With the scan tool, read Body Control Module (BCM) DTCs.
Did the DTC return?
Yes
- Go To 2
No
- Perform the appropriate INTERMITTENT CONDITION diagnostic procedure. Refer to: TESTING FOR AN INTERMITTENT CONDITION .
- SUBSTITUTE THE WIPER ON/OFF RELAY - ERASE DTCS AND CHECK FOR THE DTC TO RETURN NOTE:
When removing relays from the PDC Assembly, do not rock or wiggle the relay sideways during removal. Lift the relay upward, using fingers or suitable pliers, at the middle of the relay body and inspect the relay terminals for proper contact.
NOTE:Additional DTCs may set in other Electronic Control Units (ECU's) when substituting relays in the PDC Assembly.
- Turn the ignition off.
- Remove the relay, for the circuit being tested, from the Power Distribution Center (PDC) Assembly.
- Substitute the relay with a similar known good relay in the PDC Assembly.
- Turn the ignition on.
- With the scan tool, erase DTCs.
- Using the Environmental Data or When Monitored Conditions above, operate the vehicle under the conditions that set the DTC.
- With the scan tool, read BCM DTCs.
Did the DTC return?
Yes
- Go To 3
No
- Replace the relay that caused the fault. With the scan tool, erase any additional DTCs that may have set when the relays were substituted.
- Perform the BODY VERIFICATION TEST. Refer to: BODY VERIFICATION TEST .
- CHECK FOR VOLTAGE ON THE (W8) WIPER ON/OFF RELAY CONTROL CIRCUIT AT THE WIPER ON/OFF RELAY TERMINAL NOTE:
Make sure the Wiper Switch is in the Off position when performing this step.
- Turn the ignition off.
- Remove the relay, for the circuit being tested, from the Power Distribution Center (PDC) Assembly.
- Turn the ignition on.
- Using a DVOM, measure the voltage on the circuit being tested at the relay terminal in the PDC Assembly.NOTE:
When probing a circuit at any harness connector, always use an appropriate probing tool to prevent any possible damage to the harness connector terminals.
Is there any voltage present?
Yes
- Go To 4
No
- Go To 6
- DISCONNECT THE POWER DISTRIBUTION CENTER (PDC) ASSEMBLY HARNESS CONNECTOR(S) AND CHECK FOR VOLTAGE ON THE (W8) WIPER ON/OFF RELAY CONTROL CIRCUIT
- Turn the ignition off.
- Disconnect all Power Distribution Center (PDC) Assembly harness connectors containing the circuit being tested. Note: Use the wiring diagram as a guide to follow the path of the circuit.
- Turn the ignition on.
- Using a DVOM, measure the voltage on the circuit being tested at the PDC Assembly harness connector.NOTE:
When probing a circuit at any harness connector, always use an appropriate probing tool to prevent any possible damage to the harness connector terminals.
Is there any voltage present?
Yes
- Go To 5
No
- Go To 10
- DISCONNECT THE BCM HARNESS CONNECTOR(S) AND CHECK THE (W8) WIPER ON/OFF RELAY CONTROL CIRCUIT FOR A SHORT TO VOLTAGE
- Turn the ignition off.
- Disconnect all Electronic Control Unit (ECU) harness connectors containing the circuit being tested. Note: Use the wiring diagram as a guide to follow the path of the circuit.
- Turn the ignition on.
- Using a DVOM, measure the voltage on the circuit being tested at the PDC Assembly harness connector.NOTE:
When probing a circuit at any harness connector, always use an appropriate probing tool to prevent any possible damage to the harness connector terminals.
Is there any voltage present?
Yes
- Repair the circuit for a short to voltage.
- Perform the BODY VERIFICATION TEST. Refer to: BODY VERIFICATION TEST .
No
- Go To 11
- DISCONNECT THE BCM HARNESS CONNECTOR(S) - CHECK THE RESISTANCE ON THE (W8) WIPER ON/OFF RELAY CONTROL CIRCUIT BETWEEN THE BCM AND WIPER ON/OFF RELAY TERMINAL
- The ignition must be off when checking the resistance of a circuit.
- Disconnect all Electronic Control Unit (ECU) harness connectors 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 one lead of the DVOM to the circuit being tested at the relay terminal in the PDC Assembly.
- Connect the other lead to the circuit being tested at the ECU harness connector and measure the resistance of the circuit.NOTE:
When probing a circuit at any harness connector, always use an appropriate probing tool to prevent any possible damage to the harness connector terminals.
Is the resistance above 3.0 Ohms?
Yes
- Go To 7
No
- Go To 8
- DISCONNECT THE PDC ASSEMBLY HARNESS CONNECTOR(S) AND CHECK THE (W8) WIPER ON/OFF RELAY CONTROL CIRCUIT FOR AN OPEN OR HIGH RESISTANCE
- The ignition must be off when checking the resistance of a circuit.
- Disconnect all Power Distribution Center (PDC) Assembly harness connectors 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 one lead of the DVOM to the circuit being tested at the PDC Assembly harness connector.
- Connect the other lead to the circuit being tested at the Electronic Control Unit (ECU) harness connector and measure the resistance of the circuit.NOTE:
When probing a circuit at any harness connector, always use an appropriate probing tool to prevent any possible damage to the harness connector terminals.
Is the resistance above 3.0 Ohms?
Yes
- Repair the circuit for an open or high resistance.
- Perform the BODY VERIFICATION TEST. Refer to: BODY VERIFICATION TEST .
No
- Go To 10
- CHECK THE PDC ASSEMBLY GROUND CIRCUIT(S) FOR AN OPEN OR HIGH RESISTANCE BY LOAD TESTING THE CIRCUIT AT THE WIPER ON/OFF RELAY TERMINAL
- Turn the ignition off.
- Connect the positive lead of the load test tool to a 12 volt circuit.
- Connect the negative lead of the load test tool to the ground circuit at the relay terminal in the PDC Assembly.
- The bulb on the load test tool should be illuminated and bright if there is no resistance in the circuitry.NOTE:
Note: Why load test a circuit? A load test is used to determine if a circuit is capable of carrying the amperage needed to perform properly. The 3156 Bulb in the load tool illustrated, is a simple but effective method of testing circuit functionality. A 3156 Bulb has approximately 6.0 Ohms of resistance when the bulb is powered and draws approximately 2.0 amps of current. Read the CIRCUIT VOLTAGE DROP AND LOAD TESTING PROCEDURES for information on building a simple load test tool and for additional load testing information and alternative methods of load testing or voltage drop testing a circuit. Refer to: VOLTAGE DROP TEST PROCEDURE and CIRCUIT LOAD TESTING PROCEDURES .
NOTE:Note: A 12-volt test light can be substituted for the load test tool, but only if the test light draws enough current to effectively load test the circuit. Many high impedance test lights draw very little amperage (less than 0.1 amps) and are not reliable to load test a circuit. To perform a proper load test of a circuit, the tool being used should draw more than approximately 0.75 amps.
NOTE:Note: Why perform a Voltage Drop Test: To verify with certainty there is not any resistance in the circuit being tested, perform a simple voltage drop test across the 3156 Bulb of the load test tool. To do so perform the following:
- 1. Connect the leads of a DVOM to the alligator clips on the load test tool while the load test tool is connected in series with the circuit.
- 2. Compare the voltage drop across the bulb to the voltage reading across the Battery terminals.
- 3. The voltage dropped across the bulb should be equal to the voltage reading across the Battery terminals if there is no resistance in the circuit being tested.
Example: 2.0 Ohms of resistance in the circuit being tested will cause the voltage measurement across the bulb to be 25% less than when compared to Battery voltage. The reason for this is that the 2.0 Ohms in the circuit makes up 25% of the total circuit resistance of 8.0 Ohms. Read the CIRCUIT VOLTAGE DROP AND LOAD TESTING PROCEDURES for information on building a simple load test tool and for additional load testing information and alternative methods of load testing or voltage drop testing a circuit. Refer to: VOLTAGE DROP TEST PROCEDURE and CIRCUIT LOAD TESTING PROCEDURES .
NOTE:When probing a circuit at any harness connector, always use an appropriate probing tool to prevent any possible damage to the harness connector terminals.
NOTE:Compare the brightness of the bulb in the load test tool to that of a direct connection to Battery.
Is the load test bulb illuminated and bright?
Yes
- Go To 11
No
- Go To 9
- DISCONNECT THE PDC ASSEMBLY HARNESS CONNECTOR(S) AND CHECK THE PDC ASSEMBLY GROUND CIRCUIT(S) FOR AN OPEN OR HIGH RESISTANCE BY LOAD TESTING THE CIRCUIT
- Turn the ignition off.
- Connect the positive lead of the load test tool to a 12 volt circuit.
- Connect the negative lead of the load test tool to the ground circuit at the component harness connector (A). Note: refer to the diagram below.
- The bulb on the load test tool should be illuminated and bright if there is no resistance in the circuitry.NOTE:
Note: Why load test a circuit? A load test is used to determine if a circuit is capable of carrying the amperage needed to perform properly. The 3156 Bulb in the load tool illustrated, is a simple but effective method of testing circuit functionality. A 3156 Bulb has approximately 6.0 Ohms of resistance when the bulb is powered and draws approximately 2.0 amps of current. Read the CIRCUIT VOLTAGE DROP AND LOAD TESTING PROCEDURES for information on building a simple load test tool and for additional load testing information and alternative methods of load testing or voltage drop testing a circuit. Refer to: VOLTAGE DROP TEST PROCEDURE and CIRCUIT LOAD TESTING PROCEDURES .
NOTE:Note: A 12-volt test light can be substituted for the load test tool, but only if the test light draws enough current to effectively load test the circuit. Many high impedance test lights draw very little amperage (less than 0.1 amps) and are not reliable to load test a circuit. To perform a proper load test of a circuit, the tool being used should draw more than approximately 0.75 amps.
NOTE:Note: Why perform a Voltage Drop Test: To verify with certainty there is not any resistance in the circuit being tested, perform a simple voltage drop test across the 3156 Bulb of the load test tool. To do so perform the following:
- 1. Connect the leads of a DVOM to the alligator clips on the load test tool while the load test tool is connected in series with the circuit.
- 2. Compare the voltage drop across the bulb to the voltage reading across the Battery terminals.
- 3. The voltage dropped across the bulb should be equal to the voltage reading across the Battery terminals if there is no resistance in the circuit being tested.
Example: 2.0 Ohms of resistance in the circuit being tested will cause the voltage measurement across the bulb to be 25% less than when compared to Battery voltage. The reason for this is that the 2.0 Ohms in the circuit makes up 25% of the total circuit resistance of 8.0 Ohms. Read the CIRCUIT VOLTAGE DROP AND LOAD TESTING PROCEDURES for information on building a simple load test tool and for additional load testing information and alternative methods of load testing or voltage drop testing a circuit. Refer to: VOLTAGE DROP TEST PROCEDURE and CIRCUIT LOAD TESTING PROCEDURES .
NOTE:When probing a circuit at any harness connector, always use an appropriate probing tool to prevent any possible damage to the harness connector terminals.
NOTE:Compare the brightness of the bulb in the load test tool to that of a direct connection to Battery.
Is the load test bulb illuminated and bright?
Yes
- Go To 10
No
- Repair the ground circuit for an open or high resistance.
- Perform the BODY VERIFICATION TEST. Refer to: BODY VERIFICATION TEST .
- DISCONNECT RELATED PDC ASSEMBLY HARNESS CONNECTIONS AND INSPECT FOR PROBLEMS
- Disconnect all PDC Assembly 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.
- Perform a terminal drag test on each connector terminal to verify proper terminal tension.
Repair any conditions that are found.
- Connect all PDC Assembly 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.
- Using the recorded Environmental Data, along with the When Monitored and Set Conditions above, operate the vehicle in the conditions that set the DTC.
- With the scan tool, read BCM DTCs.
Did the DTC return?
Yes
- Replace the Power Distribution Center (PDC) Assembly in accordance with the Service Information. Refer to: POWER DISTRIBUTION CENTER (PDC), REMOVAL AND INSTALLATION .
- Perform the BODY VERIFICATION TEST. Refer to: BODY VERIFICATION TEST .
No
- Perform the BODY VERIFICATION TEST. Refer to: BODY VERIFICATION TEST .
- Test complete.
- DISCONNECT RELATED BCM HARNESS CONNECTIONS AND INSPECT FOR PROBLEMS
- Disconnect all BCM 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.
- Perform a terminal drag test on each connector terminal to verify proper terminal tension.
Repair any conditions that are found.
- Connect all BCM 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.
- Using the recorded Environmental Data, along with the When Monitored and Set Conditions above, operate the vehicle in the conditions that set the DTC.
- With the scan tool, read BCM DTCs.
Did the DTC return?
Yes
- Replace the Body Control Module (BCM) in accordance with the Service Information. Refer to: BODY CONTROL MODULE (BCM), REMOVAL AND INSTALLATION .
- Perform the BODY VERIFICATION TEST. Refer to: BODY VERIFICATION TEST .
No
- Perform the BODY VERIFICATION TEST. Refer to: BODY VERIFICATION TEST .
- Test complete.