Transaxle/Transmission Cooling

Transaxle Cooling

Pinpoint Tests

Pinpoint Test A: Motor Electronics Cooling System (MECS) Overheating

Refer to Wiring Diagram Set 54, Climate Control for schematic and connector information Electrical Diagrams.

Normal Operation

The Motor Electronics Cooling System (MECS) pump is electrically driven and controlled by the PCM through the MECS (Motor Electronics Cooling System) pump relay. The PCM energizes the MECS (Motor Electronics Cooling System) pump relay by pulling the MECS (Motor Electronics Cooling System) pump output to ground when the ignition is in the ON position.

This pinpoint test is intended to diagnose the following:

- Power Distribution Box (PDB) fuse 14 (10A)

- MECS (Motor Electronics Cooling System) coolant pump

- Wiring

- MECS (Motor Electronics Cooling System) coolant pump relay

PINPOINT TEST A : MECS (Motor Electronics Cooling System) OVERHEATING

NOTICE: Use the Flex Probe Kit for all test connections to prevent damage to the wiring terminals. Do not use standard multi-meter probes.

A1 CHECK FOR DTCs

- Connect the scan tool.

- Enter the following diagnostic mode on the scan tool: RETRIEVE.

- Carry out the PCM on-demand self test.

Are DTCs retrieved?

Yes
REFER to Computers and Control Systems Information.

No
GO to A2.

A2 CHECK PDB (Power Distribution Box) FUSE 14 (10A)

- Check fuse: PDB (Power Distribution Box) 14 (10A).

Is the fuse okay?

Yes
GO to A3.

No
REPAIR circuit CB108 (GY/YE) for a short to ground. TEST the system for normal operation.

A3 CHECK THE MECS (Motor Electronics Cooling System) COOLANT PUMP AND WIRING FOR DAMAGE

- Disconnect: MECS (Motor Electronics Cooling System) Coolant Pump C1466.

- Check the MECS (Motor Electronics Cooling System) coolant pump, wiring and harness connector for:
- pushed-out connector pins.
- bent connector pins.
- corrosion.
- broken or missing wiring insulation.


Is the MECS (Motor Electronics Cooling System) coolant pump relay, harness connector and wiring OK?

Yes
GO to A4.

No
REPAIR or INSTALL new components as necessary. TEST the system for normal operation.

A4 CHECK THE MECS (Motor Electronics Cooling System) PUMP RELAY (PDB (Power Distribution Box) RELAY 31D) HARNESS CONNECTOR AND WIRING

- Disconnect: PDB (Power Distribution Box) Relay 31D.

- Check the MECS (Motor Electronics Cooling System) coolant pump relay (PDB (Power Distribution Box) relay 31D) harness connector and wiring for:
- pushed-out connector pins.
- bent connector pins.
- corrosion.
- broken or missing wiring insulation.


Is the MECS (Motor Electronics Cooling System) coolant pump relay (PDB (Power Distribution Box) relay 31D) harness connector and wiring OK?

Yes
GO to A5.

No
REPAIR or INSTALL new components as necessary. TEST the system for normal operation.

A5 CHECK THE MECS (Motor Electronics Cooling System) COOLANT PUMP RELAY (PDB (Power Distribution Box) RELAY 31D)

- Carry out the relay component test.

Is the MECS (Motor Electronics Cooling System) pump relay (PDB (Power Distribution Box) relay 31D) OK?

Yes
GO to A6.

No
INSTALL a new MECS (Motor Electronics Cooling System) pump relay (PDB (Power Distribution Box) relay 31D). TEST the system for normal operation.

A6 CHECK CIRCUIT CB108 (GY/YE) FOR AN OPEN

- Measure the resistance between MECS (Motor Electronics Cooling System) coolant pump C1466-2, harness side and PDB (Power Distribution Box) MECS (Motor Electronics Cooling System) coolant pump relay 31D, circuit CB108 (GY/YE) socket.





Is the resistance less than 5 ohms?

Yes
GO to A7.

No
REPAIR the circuit. TEST the system for normal operation.

A7 CHECK CIRCUIT GD120 (BK/GN) FOR AN OPEN

- Measure the resistance between MECS (Motor Electronics Cooling System) coolant pump C1466-1, circuit GD120 (BK/GN), harness side and ground.





Is the resistance less than 5 ohms?

Yes
INSTALL a new MECS (Motor Electronics Cooling System) coolant pump. REFER to Motor Electronics Pump . TEST the system for normal operation.

No
REPAIR the circuit. TEST the system for normal operation.