P2257

Relay for air pump : Short circuit to ground (P2257)


Possible cause:

- M33 (electric air pump)
Affected functions:

- Engine diagnosis

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Test 1: Check component M33 (electric air pump).

1. Check component M33 (electric air pump).

Test 1.1: Check component M33 (electric air pump) by means of actuation.

Test 1.2: Check power supply of component M33 (electric air pump).

Test 1.3: Check component K40/4kO (Air pump or reserve relay).

1.1. Check component M33 (electric air pump) by means of actuation.
Test prerequisite

- Engine at idle
- Actuate component M33 (electric air pump).(Move on to actuation with button F2)


Warning!Communication with ECU required.


1.2. Check power supply of component M33 (electric air pump).
Test prerequisite

- Actuation is not OK.
Test sequence

- Switch off ignition.
- (M33) Measure direct voltage with multimeter between 2 and 1 (M33)
- Switch on ignition.
- Actuate with key F2.
Specified value

- Voltage[11.0...15.0] V







Warning!Communication with ECU required.


1.3. Check component K40/4kO (Air pump or reserve relay).

Test 1.3.1: Test current consumption of component K40/4kO (Air pump or reserve relay).

1.3.1. Test current consumption of component K40/4kO (Air pump or reserve relay).
Figure legend

- A -ConnectionTest cable 35-pin socket box
- 001 -Sockets of component N3/10 (ME-SFI [ME] control unit)
- 05 -35-pin socket box
- 050 -126-pin socket box
- 108 -Test cable 266 589 01 63 00
- N3/10 (ME-SFI [ME] control unit)
- II 1-63ConnectionTest cable
- III 64-126ConnectionTest cable
Warning!

- Connection A of test cable 108 may NOT be connected to connection B of the 126-pin socket box (050).
Continue to test with button F2







Test sequence

- Measure direct current with multimeter between sockets [F.4] 100 and [F.19] 115 of the 126-pole socket box tester.
Warning!Perform the measurement only for a short time so that component M33 (electric air pump) does not overheat.Specified value

- Amperage[0.1...0.3] A
- Component M33 (electric air pump) is switched on and is heard to run.
Question

- Is the measurement value OK?


YES
The test was okay.End of test

NO
The measurement value is not OK.Possible cause and remedy

- K40/4f32 (Fuse 32)
- Lines to component K40/4kO (Air pump or reserve relay)
- K40/4kO (Air pump or reserve relay)
End of test