P1673

P1673
Fan End-Stage - Open Circuit.

P1673
Fan End-Stage - Short Circuit to Ground.

P1673
Fan End-Stage - Short Circuit to Plus.

Function:
Two electric fans are installed to cool the coolant. The electric fans are triggered via two relays by the ECM.

Diagnostic Conditions:
A fault is recognized and stored if the engine speed is greater than 80 rpm and the battery positive voltage lies between 7.5 Volt and 17 Volt.

NOTE: The triggering power for the relay, stage 1, terminal 85 is monitored.

Wiring Diagram:




Diagnostic Procedure:

Open Circuit:

Short Circuit To Ground:

Short Circuit To B+:

1. Check both relays.
1. Remove relay.
2. Connect ohmmeter to terminals 85 and 86.

Display: approx. 75 Ohms.

2. Check wire from ECM to relays for continuity.
1. Connect special tool 9616 to wiring harness.
2. Remove relay, stage 1, coolant blower 1.
3. Remove relay, stage 1, coolant blower 2.
4. Connect ohmmeter to special tool 9616, pin 35, and relay socket, coolant blower 1, pin 2 (terminal 85).

Display: 0 - 5 Ohms.

5. Connect ohmmeter to special tool 9616, pin 35, and relay socket, coolant blower 2, pin 2 (terminal 85).

Display: 0- 5 Ohms.

If infinity Ohms is displayed, check connector X 3/1, pin 7, and wiring harness for chafing and pinching damage.

3. Check wire from ECM to relays for short circuit to ground.
1. Connect special tool 9616 to wiring harness.
2. Remove relay, stage 1, coolant blower 1.
3. Remove relay, stage 1, coolant blower 2.
4. Connect ohmmeter to special tool 9616, pin 35, and ground.

Display: Infinite Ohms.

If 0 - 5 Ohms is displayed, check wiring harness for chafing and pinching damage.

4. Check wire from ECM to relays for short circuit to B+.
1. Connect special; tool 9616 to wiring harness.
2. Remove relay, stage 1, coolant blower 1.
3. Remove relay, stage 1, coolant blower 2.
4. Connect voltmeter to special tool 9616, pin 35, and ground.
Ignition on.

Display: 0 Volt.

If battery positive voltage is displayed, check wiring harness for chafing and pinching damage.