Rest Button Nonfunctional (LI83.75-P-045751)

Publication date: 2009-01-26
Reference number: LI83.75-P-045751
Supersedes refnos: 83.75/113

REST BUTTON NONFUNCTIONAL

TECHNICAL SERVICE BULLETIN

Reference Number(s): LI83.75-P-045751 Version 2 (P-B-83.75/113, March 26, 2008), Date of Issue: January 26, 2009

Mercedes-Benz:	Model 221.171/176/177/179/186, VIN A092227 to A119911
Design Group:	83.75 Residual engine heat utilization system
Reason For Change:	Add symptom

COMPLAINT

REST Button Nonfunctional

CAUSE

If you receive customer reports in the above model vehicles of a nonfunctional REST button and the following fault codes stored, the Upper Control Panel (UCP) may have incorrect software installed.

FAULT CODES

Fault code	Fault text
9027	Event: No CAN message was received from control unit A6 (STH or HB heater unit).
9039	The red, blue, or yellow LED of switch 'N72/1s30 (STH/HB [ZUH]/residual heat button)' is defective.

REMEDY

Follow the below steps to resolve.

Using Star Diagnosis, read the software version (from Control Unit Version menu) in the UCP. If software release A221 442 20 23 is installed flash the UCP with the latest available software.
Under the "Initial startup " menu code the following components to NOT PRESENT:
1. Heated windshield
2. Stationary heater
3. Heater booster
Verify operation of the REST function.
If part(s) replacement is necessary, the control unit version and quick test printouts must be returned with the part(s).

NOTE: The following allowable labor operations should be used when submitting a warranty claim for this repair. This information has been generated on March 26, 2008. Please refer to Netstar → Star TekInfo → Star Time for the most current labor time allowance.

SYMPTOMS

Body / Remains cold / Air conditioning / Heater /

Body / Air conditioning / Insufficient heat output / Heater /

Body / Air conditioning / Residual engine heat utilization system nonfunctional / Air conditioning /

CONTROL UNIT/FAULT CODE

Control unit	Fault code	Fault text
UCP-Upper control panel (OBF8)	9027	Event: No CAN message was received from control unit A6 (STH or HB heater unit). ((ECU_ZGW_DEF_228 Standheizung (SA)@ vorhanden))
UCP-Upper control panel (OBF8)	9039	The red, blue or yellow LED of switch 'N72/1s30 (STH/HB [ZUH]/ residual heat button)' is defective. ((ECU_ZGW_DEF_228 Standheizung (SA)@vorhanden))

WORK UNITS

Op. no.	Operation text	Time	Damage code	Note
54-1011	SHORT TEST, PERFORM	0.3 hrs.	82618 90	Model Indicators: AA, AB, AC, AD, AE
54-0991	CONTROL UNIT - SOFTWARE (AFTER SHORT TEST), INSTALL	0.3 hrs.		Model Indicators: AA, AB, AC, AD, AE
54-0992	CONTROL UNIT - . CODE (AFTER SHORT TEST), PERFORM	0.1 hrs.		Model Indicators: AA, AB, AC, AD, AE