Electrical - Glow Plug Lamp/Brake Lights Inop/DTC P0571
94 06 07August 1, 2006
2012628
Condition
EPC/Glow Plug Light On, DTC P0571 Stored in ECM Memory and/or Lack of Brake Light Functionality
Customer may state EPC/Glow Plug Light On and/or brake lights inoperative or intermittent.
DTC P0571 Brake Circuit -F- Implausible Circuit stored in ECM Memory
Vehicles Affected
Technical Background
Condition may be caused by sensitive software or improperly installed brake light switch due to imprecise repair instructions.
Production Solution
No production change required.
Service
Diagnosis
If EPC light -K132- or glow plug light -K29- is ON:
^ Go to Section A.
If brake lights are not operating correctly:
^ Go to Section B.
Section A - EPC or Glow Plug Light ON
^ With key ON/engine OFF, depress brake pedal to verify proper brake light operation.
If brake lights are not operating correctly:
^ Go to Section B.
If brake lights are operating correctly:
^ Using VAS 5051/5052, check Engine Control Module (ECM) for DTC P0571.
If displayed DTC is not P0571:
^ Condition is not brake light switch related. DO NOT continue with this technical bulletin.
If displayed DTC is P0571:
^ Print GFF log and clear DTC.
^ Start engine.
^ Slowly depress brake pedal 15 times.
^ Recheck ECM for DTC.
If DTC (P0571) is found:
^ Install new brake light switch. See Installation Procedure below.
If no DTC is found:
^ Return the vehicle to customer.
Section B - Brake Lights not Operating Correctly
If vehicle brake lights do not come on or are constantly on:
^ Using VAS 5051/5052, go to Engine Electronics.
^ Read display value of measuring block 66.
Display value should be XX00 with no pedal engagement.
^ Depress brake pedal and display value should change to XX11.
If the last 2 digits of either display value are not correct:
^ Install new brake light switch. See Installation Procedure below.
^ If the last 2 digits of both display values are correct:
^ Condition is not brake light switch related. DO NOT continue with this technical bulletin.
Verify the wiring, connectors, grounds, etc. leading to the brake lights. See Repair Manual for appropriate wiring diagrams.
Installation Procedure
^ Switch ignition to the OFF position and remove ignition key.
^ Remove the lower dash cover fasteners -1-.
^ Pull cover -2- out of rear holding clips and set cover aside.
^ Disconnect wiring harness connector -1- from brake light switch -2-.
^ Remove brake light switch by turning (counterclockwise) and pulling switch out of retainer.
Obtain the new brake light switch.
Note:
DO NOT press new brake switch plunger prior to installation. Pre adjustment of plunger will result in inoperative brake lights or brake lights staying on all the time
^ Grasp brake light switch and brake light switch plunger (black arrow).
^ ^Carefully pull the plunger out to full length.
^ Apply a light coat of lubricant Part No. G052142A2 (obtained locally and considered shop supply) to the end of the plunger (black arrow).
Note:
Lubricant must be applied to prevent premature wear of brake light switch plunger.
Brake light switch can only be installed once! Installing switch a second time may result in an inoperable switch.
Leave brake pedal in resting position. DO NOT press or hold up brake pedal during brake light switch installation.
^ Carefully insert brake light switch -2- fully into mounting hole (switch will only fit in the access hole one way), pressing the plunger against the brake pedal to adjust position.
Tip:
A ratcheting sound indicates the brake light switch plunger is being set in position.
Note:
Make certain the brake light switch is installed with the wiring harness connector housing pointing upward.
^ Secure the brake light switch and plunger position by slowly turning the brake light switch full to the right (clockwise) 45 degrees, and the internal stop pin of the brake light switch is fully seated at the end of slot in outer shell.
Tip:
A click should be heard when the switch is turned to the correct position. This action also turns the plunger shoe into the correct position to make the correct electrical contacts in the switch operate as well as locks the plunger adjustment.
^ Internal stop pin (white arrow) of the brake light switch is fully seated at the end of the slot in the outer shell (black arrow) when brake light switch is correctly installed.
^ Reconnect brake light switch wiring harness connector.
If the EPC or glow plug light was blinking and there was a diagnostic code (DTC) stored in the Engine Control Module and the DTC was related to the brake light switch:
^ Connect the VAS 5051/5052 to clear DTC.
^ Create engine readiness code.
^ Depress brake pedal to verify proper function and brake light operation.
^ Install cover under dashboard.
Part return pertains to U.S. vehicles ONLY
^ When requested by WTC, return all brake light switches replaced to the address below. Include a copy of the repair order, all diagnostic printouts, and any other related documentation.
Volkswagen of America, Inc.
Warranty Test Center
3800 Hamlin Rd. - GE01
Auburn Hills, MI 48326
Warranty
Required Parts and Tools