Diagnostic Test
- CHECK FOR AN ACTIVE DTC
- With the scan tool, read DTCs and Freeze Frame Data and record on the repair order.
- With the scan tool, erase DTCs.
- Using the recorded Freeze Frame Data and the When Monitored and Set Conditions, 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 .
- INSPECT THE CHARGE AIR COOLER COOLANT PUMP FOR SIGNS OF PHYSICAL DAMAGE
- Inspect the Charge Air Cooler Coolant Pump and connector for damage due to road debris.
Is the Charge Air Cooler Coolant Pump or connector damaged or disconnected?
Yes
- Repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
No
- Go To 3
- Inspect the Charge Air Cooler Coolant Pump and connector for damage due to road debris.
- CHECK THE (F105) ELECTRIC COOLANT PUMP OUTPUT CIRCUIT FOR HIGH RESISTANCE BY LOAD TESTING THE CIRCUIT
- Disconnect the Charge Air Cooler Coolant Pump harness connector to isolate the 12.0 volt supply circuit.
- Connect the positive lead of the load test tool to the (F105) Electric Coolant Pump Output circuit at the Charge Air Cooler Coolant Pump harness connector (A). Note: refer to the diagram below.
- Connect the negative lead of the load test tool to the ground circuit of the Battery or a good chassis ground.
- Ensure that the (F105) Electric Coolant Pump Output circuit is being powered on by verifying the relay is energized and on.
- The bulb on the load test tool should be illuminated and bright if there is no resistance in the circuitry.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 LOAD TESTING PROCEDURE 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 CIRCUIT LOAD TESTING PROCEDURES .
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: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 LOAD TESTING PROCEDURE 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 CIRCUIT LOAD TESTING PROCEDURES .
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 4
No
- Repair the (F105) Electric Coolant Pump Output circuit for an open or high resistance.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
- CHECK THE (Z123) GROUND CIRCUIT FOR HIGH RESISTANCE BY LOAD TESTING THE CIRCUIT
- Disconnect the Charge Air Cooler Coolant Pump harness connector to isolate the ground circuit.
- Connect the positive lead of the load test tool to the positive side of the Battery.
- Connect the negative lead of the load test tool to the (Z123) Ground circuit at the Charge Air Cooler Coolant Pump 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: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 LOAD TESTING PROCEDURE 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 CIRCUIT LOAD TESTING PROCEDURES .
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: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 LOAD TESTING PROCEDURE 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 CIRCUIT LOAD TESTING PROCEDURES .
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
No
- Repair the (Z123) Ground circuit for an open or high resistance.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
- CHECK FOR HIGH RESISTANCE IN THE (D407) LIN BUS CIRCUIT
- Turn the ignition off.
- Disconnect the PCM-1 C1 harness connector.
- Measure the resistance of the (D407) LIN BUS circuit between the Charge Air Cooler Coolant Pump harness connector and the PCM-1 C1 harness connector.
Is the resistance below 3.0 Ohms?
Yes
- Go To 6
No
- Repair the (D407) LIN BUS circuit for an open or high resistance.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
- REPLACE THE CHARGE AIR COOLER COOLANT PUMP AND RETEST FOR DTC
- Replace the Charge Air Cooler Coolant Pump in accordance with the Service Information.
- Reconnect the PCM-1 C1 harness connector.
- Turn the ignition on.
- With the scan tool, erase DTCs.
- Cycle the ignition off, then back on
- With the scan tool, read DTCs.
Did the DTC return?
Yes
- Go To 7
No
- Replacing the Charge Air Cooler Coolant Pump repaired the fault.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
- CHECK RELATED HARNESS CONNECTIONS
- Disconnect all PCM-1 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-1 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 1 (PCM-1) 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 .

