Test KP: Charge Air Cooler Pump: Testing

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NOTE: For additional testing information, see DIAGNOSTIC AIDS .

1) For KOEO, KOER & Continuous Memory DTC P1229: Check VPWR To CAC Pump Relay Coil
DTC P1229 is set when PCM is requesting CAC pump motor to operate, but voltage is not detected on CAC circuit. Possible causes are:
- Internal Open In CAC Pump Motor
- B+ Or VPWR Circuit Open Or Shorted To Ground
- CAC Or CAC PUMP PWR Circuit Open Or Shorted To Ground
- Faulty CAC Pump Relay
- CAC Pump Motor Shorted
- Bad CAC Pump Motor Ground Connection
- Faulty PCM
Turn ignition switch to OFF position. Disconnect CAC pump relay. Turn ignition switch to ON position. Using a DVOM, measure VPWR circuit voltage at the CAC pump relay harness connector. If the voltage is greater than 10.5 volts, go to next step. If voltage is 10.5 volts or less, repair open circuit.

2) Check CAC Pump Relay

Turn ignition switch to OFF position. Remove CAC pump relay from battery junction box in engine compartment. Using a DVOM, measure resistance between relay terminals No. 1 and 2. Resistance should be 90-110 ohms. Measure resistance between relay terminal No. 1 and all other relay terminals. Resistance should be more than 10 k/ohms. See Figure and Figure . If resistance is as specified, go to next step. If resistance is not as specified, replace CAC relay.

3) Check For Open CAC Circuit Between PCM & CAC Relay

Ensure ignition switch is in OFF position. Disconnect PCM connector. Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Using a DVOM, measure resistance of CAC circuit (White/Orange wire) between PCM harness connector and CAC pump relay cavity. See PCM CONNECTOR IDENTIFICATION and Figure. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in CAC circuit.

4) Check CAC Circuit Between PCM & CAC Pump Relay For Short To PWR

Ensure CAC relay is removed from battery junction box in engine compartment. Turn ignition switch to ON position. Using a DVOM, measure voltage between negative battery terminal and CAC circuit at PCM harness connector. If voltage is less than .05 volt, go to next step. If voltage is .05 volt or more, repair short to B+ or VPWR in CAC circuit.

5) Check CAC Circuit Between PCM & CAC Pump Relay For Short To Ground

Turn ignition switch to OFF position. Using a DVOM, measure resistance between negative battery terminal and CAC circuit (White/Orange wire) at PCM harness connector. See PCM CONNECTOR IDENTIFICATION and Figure. If resistance is more than 10 k/ohms, go to next step. If resistance is 10 k/ohms or less, repair short to ground in CAC circuit.

NOTE: On some scan tools, SCICP PID may indicate ICP PID.

6) Check Status Of SCICP PID
Ensure ignition switch is turned to OFF position. Reconnect PCM connector. Reinstall CAC relay and fuses No. 23 and 106. Turn ignition switch to ON position. Using scan tool, access SCICP PID from PID/DATA MONITOR & RECORD menu. If SCICP PID value indicates OFF, check for intermittent faults. Go to TEST Z, step 1). If SCICP PID value indicates ON, proceed as follows:
- Check CAC reservoir level.
- Check for air flow blockage at CAC radiator.
- Check for high resistance or open circuit in Intake Air Temperature (IAT) 2 sensor and connecting circuits.
- Check for reversed intercooler hoses.
Repair as necessary. If no concerns are found and DTC P1229 is present in KOEO and KOER self-test, replace PCM.

NOTE: Step 7) is performed when directed here from symptom under SYMPTOMS in TROUBLE SHOOTING - NO CODES - CNG, FLEX-FUEL & GASOLINE article.

7) Check Charge Air Cooler Pump Operation
Turn ignition switch to OFF position. Using scan tool, access OUTPUT TEST MODE. See OUTPUT TEST MODE under ADDITIONAL SYSTEM FUNCTIONS. Select mode ALL ON. If charge air intercooler pump runs, check for low fluid level in intercooler system, check for cracked or incorrectly routed intercooler lines or airflow blockage at the CAC radiator. Repair as necessary. If symptom still exists, see appropriate TROUBLE SHOOTING - NO CODES article. If charge air intercooler pump does not run, go to next step.

8) Check Power And Ground Circuits At CAC Pump Motor

Turn ignition switch to OFF position. Disconnect the CAC pump. Connect scan tool to DLC. Turn ignition switch to ON position. Using scan tool, access OUTPUT TEST MODE. See OUTPUT TEST MODE under ADDITIONAL SYSTEM FUNCTIONS. Select mode ALL ON. Using DVOM, measure the voltage across the CAC pump motor harness connector. If the voltage is greater than 10.5 volts, replace CAC pump motor. If the voltage is 10.5 volts or less, go to next step.

9) Check Integrity Of CAC Pump Ground Connection

Turn ignition switch to OFF position. Disconnect the CAC pump. Using a DVOM, measure the resistance between chassis ground circuit at the CAC pump connector and battery negative terminal. If the resistance is less than 5 ohms, go to next step. If the resistance is 5 ohms or more, check the tightness of the ground lug. If tight, check wire back to the CAC connector.

10) Check B+ To CAC Pump Relay

Disconnect CAC pump relay. Using a DVOM, measure B+ circuit voltage at the CAC pump relay connector. If voltage is greater than 10.5 volts, go to next step. If voltage is 10.5 volts or less, B+ circuit has a fault. Check condition of related fuses. If fuses are okay, repair open circuit. If fuse is damaged, check B+ and CAC pump motor circuits for short to ground before replacing.

11) Check For Open CAC Pump Motor Circuit

Using a DVOM, measure resistance of the CAC pump motor circuit between the CAC pump motor relay harness connector and the pump motor harness connector. If the resistance is less than 5 ohms, replace CAC pump motor relay. If resistance is 5 ohms or more, repair open circuit.