P1157

P1157
Engine Compartment Temperature Sensor - Short Circuit to Ground.

P1158
Engine Compartment Temperature Sensor - Short Circuit to Plus.

Function:
The temperature sensor measures the engine compartment temperature. With these diagnostic trouble codes, the wire from ECM pin 16 to temperature sensor pin 1 is monitored.

Diagnostic Conditions:

P1157:
After a setting time of 2 seconds, a fault is stored if an engine compartment temperature < -42°C is measured.

P1158:
After a settling time of 2 seconds, a fault is stored if an engine compartment temperature > 135°C is measured.

Wiring Diagram:



Image Legend:
Resistance value: 2.2 - 2.6 k Ohms at 20°C

Diagnostic Procedure:



1. Check temperature sensor.
1. Remove plug on temperature sensor.
2. Connect ohmmeter to temperature sensor, pins 1 and 2.

Display: approx. 2.2 - 2.6 k Ohms at 20°C.

2. Check wire from ECM to temperature sensor for short circuit to ground.
1. Connect special tool 9616 to wiring harness.
2. Remove plug on temperature sensor.
3. Connect ohmmeter to special tool 9616, pin 16 and ground.

Display: Infinite Ohms.

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

3. Check wire from ECM to temperature sensor for short circuit to B+.
1. Connect special tool 9616 to wiring harness.
2. Remove plug on temperature sensor.
3. Connect voltmeter to special tool 9616, pin 16 and ground.
Switch on ignition.

Display: 0 Volt.

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

4. Check output voltage of ECM.
1. Connect special tool 9616.
2. Remove plug on temperature sensor.
3. Connect voltmeter to pin 16 (positive) and 34 (negative).
Switch on ignition.

Display: approx. 5 Volt.