1997 A3 1.6 AEH what relays and where??

[ali_b]

hi,

i suspect a relay problem ( not starting! but cranks ok )but i cant find information on all of them and what they control, any one know what sould be there???

the under dash relay plate has the following relays...

from left to right bottom row..No.53>No.18>No.379>No.167

on top of these is one larger black relay No.175 that has a PCB inside and nine pin outs.

are these correct??

[ali_b]

hi,

i suspect a relay problem ( not starting! but cranks ok )but i cant find information on all of them and what they control, any one know what sould be there???

the under dash relay plate has the following relays...

from left to right bottom row..No.53>No.18>No.379>No.167

on top of these is one larger black relay No.175 that has a PCB inside and nine pin outs.

are these correct??

after some searching i know Relay No.53 (Grey) controls horn electric mirrors/windows plus anything that works for about ten mins after ignition is switched off.

Relay No.18 (Grey)is load reduction relay (this one has a resistor across the non switched pins)

Relay No.379 (Black&has PCB inside)controls wash/wipe/blade park & intermitent control of front wipers.

Relay No.167 (Grey) Fuel pump

Not sure what the large black relay No.175 controls but may be alarm/central locking as it energises when pluged in whithout ignition on it also has a large PCB inside and twin relays inside plus nine pin out's.
any one know what this controls?? ECU??

[Crasher]

Relay 175 is for the starter motor inhibitor on automatic cars only; you didn’t mention your car is an automatic.

The ECU does not have a relay, power is from

Pin 1 ignition live via fuse 29

Pin 3 permanent live via fuse 10

Pin 22 cranking live from the ignition switch.

Have you done a fault code read?

[ali_b]

hi crasher, Thanks for your quick reply.

yes it is an automatic, i have done a fault code read with the following DTC's

Wednesday, 03 December 2008, 15:26:02

VAG-COM Version: Release 409.1-US



Control Module Part Number: 06A 906 019 D

Component and/or Version: 1.6l R4/2V SIMOS AT2153

Software Coding: 04030

Work Shop Code: WSC 06313

2 Faults Found:

01177 - Engine Control Unit

37-10 - Faulty - Intermittent

00537 - Lambda (Oxygen Sensor) Regulation

18-10 - Upper Limit - Intermittent


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the occasional cranking but no start i suspect the ECU has an intermittent fault is this common?
i have checked cleaned retightend the immobiliser earth and any other earth point's i could find.
No start's seem to be compleatly random more when cold/damp althogh has when warm to its got me baffled!

The O2 sensor has been replaced but fault still returns, the car is high mileage 128,000M and seems to be pinking throughout the entire rev range under light acceleration/increased load.

i cleaned and re adapted the TB and this made a massive improvement in response and acceleration/idle, still pinks although not as much, there doesnt appear to be any obvious vacume leaks, i will try a new fuel filter, then fuel pressure regulator if that fails to improve then injector's may need cleaning.

if it does start it will on first try if not then 10+ attemps or jumping it seems to help still might take 4+ trys (it has a new battery)

Any advise on what i can try before sending ECU for testing/replacement greatly received!

[Crasher]

The lambda code is of no inerest at the moment, the other code means

“01177 Engine control unit Defective, Engine will not start. Replace engine control unit”

which is straight from the VW workshop manual.