If customers complain that the engine is losing power and the engine malfunction indicator light is activated for the above vehicle, this could possibly be caused by the wiring harness of the throttle valve unit or by the throttle valve itself.
The following error codes may be stored:
- Error code `the same as`:
- P0638, `Throttle valve regulation bank 1, incorrect function`.
- P2135, `Throttle valve sensor/accelerator pedal sensor or throttle valve accelerator pedal switch signal are faulty or implausible among themselves`.
To analyze the error, the connector pins, interfaces/contacts and the wiring harness of the throttle valve must first be inspected. In addition, the throttle valve/throttle valve unit should be cleaned and the stored error codes deleted.
If the error persists, the throttle valve fault can be isolated through subsequent inspection steps. Delete the error codes again, lock the car doors and put it into 'sleep mode' (for approx. 3 minutes). Then unlock the vehicle and insert the ignition key into the ignition lock (without turning). Now depress the accelerator pedal fully.
Turn the ignition key, release the accelerator pedal after 3 seconds and start the engine. If the error codes are output again after less than 2 seconds, in association with the engine emergency mode and the warning light coming on, this suggests a faulty throttle valve as the possible cause.
In this case, the throttle valve unit must be replaced and the error codes deleted.
Then the electronically-controlled throttle valve must be re-taught. First the old basic values must be deleted using the mega macs under menu `Basic settings/Initialising adaptive functions`.
Teaching takes place with the above-described procedure for inspecting the throttle valve (lock the car doors and put it into 'sleep mode' (for approx. 3 minutes). Then unlock the car....).
Important safety notice
The following technical information and tips for practical use have been set up by HELLA in order to offer professional support to automotive workshops in their daily work. The information available here on this website is only to be used by appropriately trained specialist staff.
The reprinting, distribution, reproduction, exploitation in any form and disclosure of the contents of this document, even in part, is prohibited without our express written approval and indication of the source. The schematic illustrations, figures and descriptions are for explanation and presentation of the document text and cannot be used as a basis for installation or design. All rights reserved.
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