Engine Fan Runs Constantly (20.40/26A)

Publication date: 2004-10-26
Reference number: 20.40/26A
Supersedes refnos: 20.40/26

ENGINE FAN RUNS CONSTANTLY

TECHNICAL SERVICE BULLETIN

Reference Number(s): P-B-20.40/26A, Date of Issue: October 26, 2004

MERCEDES-BENZ:	Model 209.375/376/475/476
GROUP:	20 - Engine Cooling System

Superceded Bulletin(s): P-B-20.40/26, Date of Issue: December 16, 2003

NOTE: Revision: Technical Content Updated

SUBJECT

Model 209.375/376/475/476

Engine Fan Runs Constantly

If you receive customer reports in the above model vehicles of the engine fan running constantly with code P2073(004) Electric fan for engine & AC, open circuit; this may be caused by the wiring harness between the ECU and the engine fan or the engine control unit fan end stage malfunctioning. To resolve, perform the below procedure.

NOTE: Only vehicles as outlined in Service Campaign Bulletin No. 2003110006 are affected, see vehicle range below:

VEHICLES AFFECTED

Model	Chassis End Number
Model	From	To
209.375	000313	090256
209.376	019833	088796
209.475	000115	017659
209.476	009165	017642

When performing Service Campaign Bulletin No. 2003110006 only, the engine ECU does not need to be exchanged. All engine ECUs exchanged under warranty for the above condition must be accompanied by the freeze frame data for the respective DTC. Claims submitted without this information will be debited back to the dealer.

Remedy:

Check wiring harness between engine ECU connector (pin 39) and engine fan connector (pin 4) for continuity. IF OK, proceed as follows.
Replace engine control unit (AR07.08-P-7008P)
Install adapter harness
1. Remove lower underbody panel
2. Disconnect engine wiring harness plug from engine fan
3. Connect adapter wiring harness between fan connector and engine wiring harness.
4. Secure adapter wiring harness with loom ties (Fig 1 ).
5. Secure adapter wiring harness plug to engine fan (Fig 2 ).
6. Reinstall lower underbody panel.
Fig 1: Securing Adapter Wiring Harness With Loom Ties

Fig 2: Securing Adapter Wiring Harness Plug To Engine Fan

PARTS INFORMATION

Qty.	Part Name	Part Number
1	Adaptor wiring harness	A209 540 56 35

NOTE: The following allowable labor operations should be used when submitting a warranty claim for this repair.

IN CASE OF WARRANTY

Operation: Short test, perform (54-1011) Fuel injection control module, replace (07-1628) Suction fan adapter wiring harness, install (02-4123)

WARRANTY INFORMATION

Damage Code	Operation Number	Time (hrs.)	Model Indicator (s)
54575 73	54 1011	0.3 hrs.	00
	07 1628	0.4 hrs.	S2, S3, S5, S6
	02 4123	0.7 hrs.	S2, S3, S5, S6