Pinpoint Test C: P0645, P0646, P0647
- Refer to Wiring Diagrams AUTOMATIC CLIMATE CONTROL SYSTEM
for schematic and connector information.
Normal Operation and Fault Conditions
Voltage is provided to the A/C clutch relay coil. When A/C is requested and A/C line pressures allow, a ground is provided to the A/C clutch relay coil from the PCM, energizing the A/C clutch relay. A/C Request, REFER to: Climate Control System - Vehicles With: Electronic Manual Temperature Control (EMTC) - System Operation and Component Description .
DTC Fault Trigger Conditions
DTC Description Fault Trigger Condition PCM P0645:00 A/C Clutch Relay Control Circuit: No Sub Type Information This DTC sets when the PCM grounds the relay circuit and more current than expected is detected on the relay circuit. The DTC also sets when the relay circuit is off and voltage is detected on the relay circuit. PCM P0646:00 A/C Clutch Relay Control Circuit Low: No Sub Type Information T his DTC sets when the relay circuit is off and ground is detected on the relay circuit. The PCM expects to detect voltage coming through the relay coil to the relay circuit when it is not grounding it. PCM P0647:00 A/C Clutch Relay Control Circuit High: No Sub Type Information This DTC sets when the PCM grounds the relay circuit and excessive current draw (short to voltage) is detected on the relay circuit. Possible Sources
- Fuse
- Wiring, terminals or connectors
- A/C clutch relay (non-serviceable, part of the BJB)
- PCM
Visual Inspection and Pre-checks
- Verify BJB fuse 53 (10A) is OK.
- NOTE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may cause damage to the connector.
- C1 CHECK THE A/C (AIR CONDITIONING) CLUTCH RELAY COIL CONTROL CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect PCM C1235B (1.5L), C1915B (2.0L) or C175B (2.5L).
- Disconnect BJB C1035B.
- Ignition ON.
- Measure:
Positive Lead Measurement / Action Negative Lead C1035B-21 Ground
Is any voltage present?
Yes REPAIR the circuit. No GO to C2 - C2 CHECK THE A/C (AIR CONDITIONING) CLUTCH RELAY COIL CONTROL CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Measure:
Positive Lead Measurement / Action Negative Lead C1035B-21 Ground
Is the resistance greater than 10, 000 ohms?
Yes GO to C3 No REPAIR the circuit. - C3 CHECK THE A/C (AIR CONDITIONING) CLUTCH RELAY COIL CONTROL CIRCUIT FOR AN OPEN
- For vehicles equipped with a 1.5L engine, measure:
Positive Lead Measurement / Action Negative Lead C1035B-21 C1235B-2
- For vehicles equipped with a 2.0L engine, measure:
Positive Lead Measurement / Action Negative Lead C1035B-21 C1915B-62
- For vehicles equipped with a 2.5L engine, measure:
Positive Lead Measurement / Action Negative Lead C1035B-21 C175B-58
Is the resistance less than 3 ohms?
Yes GO to C4 No REPAIR the circuit. - For vehicles equipped with a 1.5L engine, measure:
- C4 CHECK FOR CORRECT PCM (POWERTRAIN CONTROL MODULE) OPERATION
- Ignition OFF.
- Disconnect and inspect all PCM electrical connectors (if not previously disconnected).
- Repair:
- corrosion (install new connector or terminal - clean module pins)
- damaged or bent pins - install new terminals or pins
- pushed-out pins - install new pins as necessary
- Connect all PCM electrical connectors. Make sure they seat and latch correctly.
- Operate the system and determine if the concern is still present.
Is the concern still present?
Yes CHECK OASIS for any applicable service articles: TSB, GSB, SSM or FSA. If a service article exists for this concern, DISCONTINUE this test and FOLLOW the service article instructions. If no service articles address this concern, Refer to PCM Guided Routine Testing No The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. ADDRESS the root cause of any connector or pin issues.