Diagnostic Test

1. Check for any applicable Service Bulletins or Flash updates related to the DTC.

   Are there any applicable Service Bulletins or Flash updates?

   Yes 

   • Perform the applicable repair.
   • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

   No 

   • Go To  2

1. With the scan tool, read DTCs in all Electronic Control Units (ECUs) and record on the repair order.
2. For future reference, with the scan tool, run and save a vehicle Scan Report and all related recorded data.
3. With the scan tool, erase all DTCs.
4. Turn the ignition off for a minimum of 10.0 seconds.
5. Turn the ignition on.
6. Using the When Monitored and Set Conditions above and recorded data, operate the vehicle in the conditions that set the DTC.
7. With the scan tool, read DTCs.

Did the DTC return?

Yes 

• Go To  3

No 

• Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .

1. Refer to the recorded DTCs.

   Are there any Run/Start Relay Control circuit DTCs present in any other modules?

   Yes 

   • Perform the applicable diagnostic procedure(s).

   No 

   • Go To  4

1. Check the Power Distribution Center layout in the wiring information to determine if the Vacuum Pump Relay is removable or a Printed Circuit Board (PCB) Relay in the PDC.

   What type of relay is the vehicle configured with?

   Removable Relay 

   • Go To  5

   PCB Relay 

   • Go To  6

1. Turn the ignition off.
2. Remove the Vacuum Pump Relay from the relay connector in the PDC.
3. Turn the ignition on.
4. Using a 12-volt test light connected to ground, probe the Battery supply voltage from the Run/Start Relay Output at terminal 85 at the Vacuum Pump Relay connector in the PDC.

   Is the test light illuminated and bright?

   Yes 

   • Go To  7

   No 

   • Check all of the fuses in the PDC. If a fuse is open, replace the fuse and retest. If no problems are found with the fuses, check the Battery supply to the PDC and the operation of the Run/Start Relay. If no problems are found replace the PDC in accordance with the Service Information.
   • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

1. Using a DVOM, back probe and measure the voltage on the Vacuum Pump Relay (T110) Control circuit at the PDC connector.
   NOTE:

   The relay must be commanded off when checking for voltage on the circuit. With the relay Low Side Driver control circuit commanded off the voltage should be approximately equal to Battery voltage on the (T110) Vacuum Pump Relay Control circuit.

   Is the voltage approximately equal to Battery voltage?

   Yes 

   • Go To  7

   No 

   • Check all of the fuses in the PDC. If a fuse is open, replace the fuse and retest. If no problems are found with the fuses, check the Battery supply to the PDC and the operation of the Run/Start Relay. If no problems are found replace the PDC in accordance with the Service Information.
   • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

1. If the relay is removable, reinstall the Vacuum Pump Relay in the PDC.
2. Turn the ignition on.
3. Using a 12-volt test light connected to ground, back probe the Vacuum Pump Relay (T110) Control circuit at the PDC connector.
   NOTE:

   The relay should make an audible click when closing. Another way to verify that the relay closed is to back probe and check for voltage on the relay output circuit.

   Did the relay close when connecting the Vacuum Pump Relay (T110) Control circuit to ground through the test light?

   Yes 

   • Go To  8

   No 

   • If this is a PCB relay, replace the Power Distribution Center (PDC) in accordance with the Service Information.
   • If this is a removable relay and the PDC has an internal PCB and harness connectors, isolate and check the continuity between terminal 86 of the relay connector and the output terminal at the PDC connector. If the resistance is below 3.0 Ohms, replace the Vacuum Pump Relay. If the resistance is above 3.0 Ohms, replace the Power Distribution Center (PDC) in accordance with the service information. Refer to CENTER, POWER DISTRIBUTION (PDC), REMOVAL AND INSTALLATION .
   • If this is a removable relay and the wiring harness is directly hard wired into the PDC, replace the Vacuum Pump Relay.
   • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

1. The ignition must be off when checking a circuit for continuity to ground.
2. 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.
3. Connect the negative lead of the DVOM to a known good ground.
4. 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.

1. If it is necessary to probe a terminal at a PCM harness connector, connect the (special tool #10436, Adapter, GPEC Diagnostic) to the appropriate PCM harness connector.
   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

1. The ignition must be off when checking the continuity of a circuit.
2. 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.
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 component harness connector.
5. Connect the other lead to the circuit being tested at the GPEC Adaptor and measure the resistance of the circuit.

1. If it is necessary to probe a terminal at a PCM harness connector, connect the

   (special tool #10436, Adapter, GPEC Diagnostic)

   to the appropriate PCM harness connector.

   NOTE:

   The GPEC Diagnostic Adaptor can add up to 1.5 Ohms of resistance to the circuit.

   Is the resistance below 3.0 Ohms?

   Yes 

   • Go To  10

   No 

   • Repair the circuit for an open or high resistance.
   • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

1. Perform any Service Bulletins that apply.
2. Disconnect all PCM harness connectors.
3. Disconnect all related in-line harness connections (if equipped).
4. Disconnect the related component harness connectors.
5. 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.

6. Reconnect all PCM harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
7. Reconnect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
8. Reconnect all related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
9. With the scan tool, erase DTCs.
10. Test drive or operate the vehicle in accordance with the when monitored and set conditions.
11. 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 

    • The wiring or poor connection problem has been repaired.
    • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .