If a customer complains that the engine malfunction indicator light, for the above-mentioned vehicle, is activated and the engine judders or accelerates poorly, the possible source of error could be the coolant temperature sensor. The following error codes may be stored: Error code `the same as`:
- P0122,`Throttle valve sensor, accelerator pedal sensor or switch A, signal is too low`.
- P0131,`Lambda sensor bank 1, signal is too low`.
A malfunction could be triggered by a leak inside the 2-pin coolant temperature sensor (which is installed in the electrical thermostat). It is also possible that cooling water has entered the wiring harness or the control unit through a capillary effect, causing problems in the electrics/electronics.
If during this inspection/visual check, water is detected in the wiring harness casing or oxidation is detected on the control unit and connectors, then the control unit must also be checked/replaced.
The coolant temperature sensor is available from the Hella spare part product range. Spare part no.: 6PT 009309-221
Before carrying out the repair it is recommended that you check the signals and the signal transmission for the accelerator pedal sensor, throttle valve sensor and lambda sensor with regard to the stored error codes, and that you then delete the error codes.
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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