Diagnostic Instructions
Circuit Description
The supercharger intercooler relay is a normally open relay. The relay armature is held in the open position by spring tension. The ignition 1 voltage is supplied directly to the relay coil and to the armature contact when the ignition is ON, or
the engine is running. The engine control module (ECM) supplies the ground path to the relay coil control circuit via an internal integrated circuit called an output driver module (ODM). When the engine is running , the ECM commands the relay ON, and the relay
coil creates an electromagnetic field. This electromagnetic field overcomes the spring tension and pulls the armature contact into the stationary contact of the relay load circuit. The closing of the relay contacts allow current to flow from the battery to the
supercharger intercooler pump. When the ignition switch is turned to the OFF position, power is interrupted to the output driver module in the ECM and the relay electromagnetic field collapses. This allows the spring tension to separate the relay armature contact
from the relay load circuit contact, which interrupts current flow to the supercharger intercooler pump.
Diagnostic Aids
• | A slight resistance of 1-4 ohms on the B+ or ground circuits to the CAC coolant pump or the CAC coolant pump relay may inhibit the supercharger coolant pump operation. |
• | This test procedure assumes that the vehicle battery has passed a load test and is completely charged. Refer to
Battery Inspection/Test
. |
• | When disconnecting electrical connectors or removing fuses and relays from a fuse block, always inspect the component electrical terminals for corrosion and the mating electrical terminals for correct tension. |
Reference Information
Schematic Reference
Engine Controls Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References
for scan tool information
Special Tools
J 43244
Relay Puller Pliers
Circuit/System Verification
- Ignition ON, command the CAC Coolant Pump ON and OFF with a scan tool. Listen for the CAC coolant pump to turn ON and OFF with each command.
- Verify that the charge air cooler (CAC) coolant level is full. Refer to
Cooling System Leak Testing
,
Charge Air Cooling System Coolant Level Inspection
, and
Charge Air Cooling System Draining and Filling
.
Circuit/System Testing
- Ignition OFF, disconnect the CAC coolant pump relay.
- Ignition ON, verify that a test lamp does not illuminate between the control circuit and ground.
⇒ | If the test lamp illuminates, test the control circuit for a short to voltage. |
- Verify that a test lamp illuminates between the coil voltage supply circuit and ground.
⇒ | If the test lamp does not illuminate, test the B+ coil supply circuit for a short to ground or an open/high resistance. |
- Verify that a test lamp illuminates between the B+ switch supply circuit and ground.
⇒ | If the test lamp does not illuminate, test the B+ switch supply circuit for an open/high resistance. If the circuit tests normal and the B+ switch supply circuit fuse is open, test the CAC pump voltage supply circuit for a short to ground. |
- Disconnect the harness connector at the CAC coolant pump.
- Test for less than 2 ohm between the CAC coolant pump ground circuit terminal 1 and ground.
⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
- Connect the harness connector at the CAC coolant pump.
- Connect a 10A fused jumper wire between the B+ switch circuit and the CAC coolant pump voltage supply circuit. Verify that CAC coolant pump is activated.
⇒ | If the CAC coolant pump does not activate, test the CAC coolant voltage supply circuit for an open/high resistance. If the circuit tests normal, test the CAC coolant pump motor. |
- Connect a test lamp between the B+ coil supply circuit and the CAC relay control circuit.
- Command the CAC coolant pump ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between commanded states.
⇒ | If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the ECM. |
⇒ | If the test lamp is always OFF, test the control circuit for an open/high resistance. If the circuit tests normal, replace the ECM. |
- If all circuits test normal, test or replace the CAC coolant pump relay.
Component Testing
Coolant Pump Relay
- Ignition OFF, disconnect the CAC coolant pump relay.
- Test between the normally-closed switch terminals, if any, for 0 ohms.
- Test between the normally-open switch terminals for infinite ohms.
- Test between each switch terminal and either coil terminal for infinite ohms.
- Connect the relay coil terminals to ground and fused power to energize the relay.
- Test between each switch terminal and each coil terminal for 0 volts.
- Test between the normally-closed switch terminals, if any, for infinite ohms.
- Test between the normally-open switch terminals for 0 ohms.
⇒ | If the relay fails any of the above tests, replace the supercharger coolant pump relay. |
CAC Pump Dynamic Test
- Install a 10A fused jumper wire between the B+ terminal 2 and 12 volts.
- Install a jumper wire between the ground terminal 1 and ground.
- Observe for the CAC pump to activate.
⇒ | If the CAC pump does not activate, replace the CAC coolant pump. |
Repair Instructions
Perform the
Diagnostic Repair Verification
after completing the repair.