Engine/Eng. Controls - Crank, No Start/ECT Sensor Faults
SI M11 01 11Engine
July 2012
Technical Service
This Service Information bulletin supersedes SI M11 01 11 dated February 2012.
[NEW] Note: N16 and N14 JCW engines have been removed. For diagnosing N16 and N14 JCW engines, refer to SI M11 04 12.
[NEW] designates changes to this revision
SUBJECT
[NEW] N18: Engine Crank, No Start and/or Engine Coolant Temperature Sensor Faults
MODEL
[NEW] R55, R56, R57, R58, R59 and R60
SITUATION 1
The engine either exhibits a crank, no start or a hard start (long crank) usually on a cold engine. No faults are stored in the DME.
[NEW] SITUATION 2
The Service Engine Soon lamp is illuminated with one or more of the following fault codes stored:
N18
^ 0x2943 coolant temperature sensor, signal change too fast
^ 0x2937 coolant temperature sensor, electrical: short circuit to positive
^ 0x2936 coolant temperature sensor, electrical: short circuit to earth
^ 0x293A coolant temperature sensor, plausibility, cold start: temperature too high
^ 0x2947 coolant temperature sensor, signal: fixed on low
CAUSE
Poor solder contacts in the engine coolant temperature sensor.
The sensor is integrated into the engine thermostat housing.
[NEW] PROCEDURE
1. If no fault codes are stored:
^ Using ISTA/D, read out the ambient air temperature and engine coolant temperature in the DME through Diagnostic Query.
^ If the vehicle has been sitting overnight, these two temperatures should be within +/- 2°C.
^ If the engine coolant temperature is still showing a hot or warm engine, the engine coolant temperature sensor has failed. Replace the engine thermostat.
2. If fault codes are stored:
^ Replace the engine thermostat.
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.
PARTS INFORMATION
WARRANTY INFORMATION