P2257

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


Possible cause:

- N10/1kP (Secondary air injection relay)
- N10/1kR (Air pump or oil cooler fan relay)
- N10/1f61 (Fuse 61)
Affected functions:

- Engine diagnosis

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Test 1: Arrangement of fuses

Test 2: Check component N10/1kR (Air pump or oil cooler fan relay).

1. Arrangement of fuses
Figure legend/figure

- N10/1 (Driver-side SAM control unit with fuse and relay module)
Fuses

- FuseF43-F67
Relays

- I =N10/1kI (Circuit 87 relay, engine)
- K =N10/1kK (Circuit 87 relay, chassis)
- L =N10/1kL (Starter relay)
- M =N10/1kM (SEQ [ASG] pump control relay)
- N =N10/1kN (Circuit 15 relay)
- O =N10/1kO (FAN relay module)
- P =N10/1kP (Circuit 15R relay)
- R =N10/1kR (Air pump or oil cooler fan relay)







2. Check component N10/1kR (Air pump or oil cooler fan relay).

Test 2.1: Test current consumption of component N10/1kR (Air pump or oil cooler fan relay).

2.1. Test current consumption of component N10/1kR (Air pump or oil cooler fan 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

- Switch off ignition.
- Connect socket box (126-pin) to component N3/10 (ME-SFI [ME] control unit).
- Measure direct current with multimeter between sockets [F.4] 100 and [F.19] 115 of the 126-pole socket box tester.
- Switch on ignition.
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

- N10/1f61 (Fuse 61)
- Lines to component N10/1kR (Air pump or oil cooler fan relay)
- N10/1kR (Air pump or oil cooler fan relay)
End of test