Engine Controls - Crank, No Start/ECT Sensor Faults Stored

SI M11 04 12
Engine

July 2012
Technical Service

SUBJECT
N14 JCW or N16: Engine Crank, No Start and/or Engine Coolant Temperature Sensor Faults

MODEL
JCW with N14 engine produced from 6/2010

All models with N16

SITUATION 1
The engine either exhibits a crank, no start or a hard start (long crank), usually when cold. No faults are stored in the DME.

SITUATION 2
The Service Engine Soon lamp is illuminated with one or more of the following fault codes stored:

N16

^ 2F1A coolant temperature sensor, signal

^ 2F22 engine temperature, plausibility

^ 2F19 coolant temperature sensor, signal

^ 2F15 coolant temperature sensor, plausibility

^ 2F16 coolant temperature sensor, plausibility

JCW with N14

^ 2F1A coolant-temperature sensor, signal

^ 2F22 engine temperature, plausibility

^ 2F19 coolant-temperature sensor, signal

^ 2F23 engine temperature plausibility

CAUSE
Poor solder contacts in the engine coolant temperature sensor.

The sensor is integrated into the engine thermostat housing.

PROCEDURE
If no fault codes are stored:

1. Using ISTA/D, read out the ambient air temperature and engine coolant temperature in the DME through Diagnostic Query.

2. If the vehicle has been sitting overnight, these two temperatures should be within +/- 2°C.

3. If the engine coolant temperature is still showing a hot or warm engine, the engine coolant temperature sensor has failed.





4. Replace the engine thermostat with P/N 11 53 7 534 521 and adapter harness 12 51 7 646 145 (1).

Note:
If the ISTA system message displays: "Battery voltage only "XX.XX" V. Please connect charger", connect an approved charger and note the displayed battery voltage reading in the repair order comments section.





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