Powertrain Controls - ECM/PCM

Code 52 Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION:

The engine oil temperature sensor uses a thermistor to control the signal voltage to the ECM. When the engine is cold, the sensor resistance is high, therefore, the ECM will see a low voltage. The engine oil temperature sensor is not used by the ECM to determine any calibration values. This sensor information is processed in the ECM and sent across serial data, on circuit 800, to the Central Control Module (CCM) for use in determining when to change the engine oil.

TEST DESCRIPTION: Numbers below refer to circled numbers on the diagnostic chart.

1. Code 52 will set if:

^ Time since engine start is 30 minute.
^ Signal voltage indicates engine oil temperature below -35~C (-31~F).

2. A code 52 will set, due to an open sensor, wire or connection. This test will determine if the wiring and ECM are OK.

3. This will determine if the engine oil temperature signal Circuit 1313 or the sensor ground circuit 452 is open.


DIAGNOSTIC AIDS:

^ If code 52 was set; the CCM's oil life monitor system has been calculating the engine oil life with false information. The oil life monitor must be reset and the engine oil and filter may be changed.

^ A Scan tool reads temperature of the oil in the engine and should read close to ambient air temperature on a cold engine and rise as engine oil temperature increases.

^ A faulty connection, or an open in CKT 1313 or 452, will result in a code 52. If code 15 or 21 is also set, check CKT 452 for faulty wiring or connections.

^ Carfully check harness and connections for possible open on circuits 901 or 452. Refer to TESTING PROCEDURES/DIAGNOSIS BY SYMPTOM/INTERMITTENTS..