Diagnostic Test

1. Perform any Service Bulletins that may apply.
2. Turn the ignition on.
3. For future reference, with the scan tool, run and save a vehicle Scan Report and all related recorded data.
4. With the scan tool, read DTCs and record on the repair order.
5. With the scan tool, erase all DTCs.
6. Start the engine and run for two minutes.
7. Turn the steering wheel from stop to stop.
8. With the scan tool, read the EPS DTCs.

   Did the DTC return?

   Yes 

   • Go To  2

   No 

   • The condition or conditions that originally set this DTC are not present at this time. Using the wiring diagrams as a guide, check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals, and correct pin tension and repair as necessary. If no problems are found, test complete.
   • Perform the EPS VERIFICATION TEST. Refer to EPS VERIFICATION TEST .

1. Refer to the recorded DTCs.

   Are there any EPS or Communication related DTCs present?

   Yes 

   • Perform the applicable diagnostic procedure(s). Refer to DTC INDEX (1 OF 3) and/or DTC INDEX (2 OF 3) and/or DTC INDEX (3 OF 3) .

   No 

   • Go To  3

1. The ignition must be off when checking a circuit for continuity to ground.
2. Remove the F08 80A and the F17 80A Fuses from the Power Distribution Center (PDC).
3. Isolate the circuit by disconnecting the EPS Module C1 harness connector and the EPS Module C2 harness connector. Note:  Use the wiring diagram as a guide to follow the path of the circuit.
4. Connect the negative lead of the DVOM to a known good ground.
5. With the positive lead of the DVOM, probe the circuits being tested at the EPS Module C1 and C2 harness connectors and check for continuity between the circuit and ground.

Is there continuity between ground and the circuit being tested?

Yes 

• Repair the Fused B(+) circuits for a short to ground.
• Perform the EPS VERIFICATION TEST. Refer to EPS VERIFICATION TEST .

No 

• Go To  4

1. The ignition must be off when checking the continuity of a circuit.
2. Isolate the circuit by disconnecting the EPS Module C1 harness connector and the PDC C10 harness connector. Note:  Use the wiring diagram as a guide to follow the path of the circuit.
3. 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.
4. Connect one lead of the DVOM to the circuit being tested at the PDC C10 harness connector.
5. Connect the other lead to the circuit being tested at the EPS Module C1 harness connector and measure the resistance of the circuit.

Is the resistance below 3.0 Ohms?

Yes 

• Go To  5

No 

• Repair the (A10) Fused B(+) circuit for an open or high resistance.
• Perform the EPS VERIFICATION TEST. Refer to EPS VERIFICATION TEST .

1. The ignition must be off when checking the continuity of a circuit.
2. Isolate the circuit by disconnecting the EPS Module C1 harness connector and the PDC C11 harness connector. Note:  Use the wiring diagram as a guide to follow the path of the circuit.
3. 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.
4. Connect one lead of the DVOM to the circuit being tested at the PDC C11 harness connector.
5. Connect the other lead to the circuit being tested at the EPS Module C2 harness connector and measure the resistance of the circuit.

Is the resistance below 3.0 Ohms?

Yes 

• Go To  6

No 

• Repair the (A230) Fused B(+) circuit for an open or high resistance.
• Perform the EPS VERIFICATION TEST. Refer to EPS VERIFICATION TEST .

1. The ignition must be off when performing a resistance check to find a short between circuits.
2. Isolate the circuit by disconnecting the EPS Module C1 harness connector containing the circuits being tested. At this time leave all in-line connectors connected. Note: Use the wiring diagram as a guide to follow the path of the circuit.
3. Connect one lead of the DVOM to the circuit being tested at the EPS Module C1 harness connector.
4. With the other lead of the DVOM probe all other circuits at the EPS Module C1 harness connector.

Is there continuity between the circuit being tested and any other circuit?

Yes 

• Repair the short between the circuits that have continuity. Use the wiring diagram as a guide to trace the circuits and look for any in-line connectors to help isolate the location of the short.
• Repair the (Z942) Ground circuit for a short.
• Perform the EPS VERIFICATION TEST. Refer to EPS VERIFICATION TEST .

No 

• Go To  7

1. The ignition must be off when performing a resistance check to find a short between circuits.
2. Isolate the circuit by disconnecting the EPS Module C2 harness connector containing the circuits being tested. At this time leave all in-line connectors connected. Note: Use the wiring diagram as a guide to follow the path of the circuit.
3. Connect one lead of the DVOM to the circuit being tested at the EPS Module C2 harness connector.
4. With the other lead of the DVOM probe all other circuits at the EPS Module C2 harness connector.

Is there continuity between the circuit being tested and any other circuit?

Yes 

• Repair the short between the circuits that have continuity. Use the wiring diagram as a guide to trace the circuits and look for any in-line connectors to help isolate the location of the short.
• Repair the (Z948) Ground circuit for a short.
• Perform the EPS VERIFICATION TEST. Refer to EPS VERIFICATION TEST .

No 

• Go To  8

1. The ignition must be off when checking the continuity of a circuit.
2. Isolate the circuit by disconnecting the EPS Module C1 harness connector. Note:  Use the wiring diagram as a guide to follow the path of the circuit.
3. 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.
4. Connect positive lead of the DVOM to the circuit being tested at the EPS Module C1 harness connector.
5. Connect the negative lead of the DVOM to a known good ground.

Is the resistance below 3.0 Ohms?

Yes 

• Go To  9

No 

• Repair the (Z942) Ground circuit for an open or high resistance.
• Perform the EPS VERIFICATION TEST. Refer to EPS VERIFICATION TEST .

1. The ignition must be off when checking the continuity of a circuit.
2. Isolate the circuit by disconnecting the EPS Module C2 harness connector. Note:  Use the wiring diagram as a guide to follow the path of the circuit.
3. 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.
4. Connect positive lead of the DVOM to the circuit being tested at the EPS Module C2 harness connector.
5. Connect the negative lead of the DVOM to a known good ground.

Is the resistance below 3.0 Ohms?

Yes 

• Go To  10

No 

• Repair the (Z948) Ground circuit for an open or high resistance.
• Perform the EPS VERIFICATION TEST. Refer to EPS VERIFICATION TEST .

1. Disconnect the EPS Module C1 and C2 harness connectors.
2. Disconnect all related in-line harness connections (if equipped).
3. Disconnect the related component harness connectors.
4. 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.

5. Connect the EPS Module harness connectors. Be certain that the harness connectors are fully seated and the connector locks are fully engaged.
6. Connect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
7. Connect the related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
8. With the scan tool, erase DTCs.
9. Using the recorded Event and Environmental Data, along with the When Monitored and Set Conditions above, operate the vehicle in the conditions that set the DTC.
10. With the scan tool, read EPS Module DTCs.

    Did the DTC return?

    Yes 

    • Replace the Electric Power Steering (EPS) Module in accordance with Service Information. Refer to GEAR, REMOVAL AND INSTALLATION .
    • Perform the EPS VERIFICATION TEST. Refer to EPS VERIFICATION TEST .

    No 

    • Perform the EPS VERIFICATION TEST. Refer to EPS VERIFICATION TEST .
    • Test complete.