Couple of things I need to correct.
1. The so called Load Reduction Relay J59 - marked "100" which is located next to the ECU J271 relay, is in fact the Secondary Air Injection (SAI) Pump J299 Relay aka "100" relay. Have installed the revised 100 relay which is now "644" light-green relay - part# 4H0951253 for anyone who wants to look it up. From the WD, I can see this has no bearing with the ECU relay anyway.
2. Apologies, Pin 3/86 on the ECU J271 relay is in fact just 'looped' from Pin 1/30 on the relay housing which has permanent +12v , so this also has +12v whether IGN on or off
Worth a try, but as I thought placing a GND wire directly onto the ECU casing did nothing.
I took apart the ECU relay housing to double check wiring at the relay box - every single wire looks perfect at the relay housing with no corrosion or breaks that are visible.
I have tested the ECU + ECU relay wiring with a DVM and also using continuity resistance 'buzzer' tests to check and verify end-to-end track paths.
-So, as mentioned previously and HMC has confirmed - if the ECU relay Pin 5/85 is supposed to be receiving +12v trigger from the ECU T121/21 - and it's exhibiting "0.5v" with IGN off and "0.35v" with IGN on, then this MUST mean there is resistance / faulty connection in the earth/ground path to the ECU or leading to the ECU.
Wiki suggests:
As mentioned previously, measuring at the ECU harness (with the ECU out and IGN on or off):
T121/1 GND ok
T121/2 GND ok
T121/3 +12v ok via 15a Fuse 29
I've checked, cleaned and re-seated all the 3-main GND points in the plenum chamber, one of which is next to the ECU itself. Plus, the other couple of GND points in the engine bay - one with the Coil Pack harness by the coils and the other below the left side headlight near the air-box.
The only other GND point that I can think that 'may' have some bearing is the one on the IGN switch housing.. but I suspect that's ok as I have power to everything with IGN on.
I can work if a wire(s) has a break or relay is faulty etc etc... but this has really got me stumped.. Not sure where else to look ?
1. The so called Load Reduction Relay J59 - marked "100" which is located next to the ECU J271 relay, is in fact the Secondary Air Injection (SAI) Pump J299 Relay aka "100" relay. Have installed the revised 100 relay which is now "644" light-green relay - part# 4H0951253 for anyone who wants to look it up. From the WD, I can see this has no bearing with the ECU relay anyway.
2. Apologies, Pin 3/86 on the ECU J271 relay is in fact just 'looped' from Pin 1/30 on the relay housing which has permanent +12v , so this also has +12v whether IGN on or off
Worth a try, but as I thought placing a GND wire directly onto the ECU casing did nothing.
I took apart the ECU relay housing to double check wiring at the relay box - every single wire looks perfect at the relay housing with no corrosion or breaks that are visible.
I have tested the ECU + ECU relay wiring with a DVM and also using continuity resistance 'buzzer' tests to check and verify end-to-end track paths.
-So, as mentioned previously and HMC has confirmed - if the ECU relay Pin 5/85 is supposed to be receiving +12v trigger from the ECU T121/21 - and it's exhibiting "0.5v" with IGN off and "0.35v" with IGN on, then this MUST mean there is resistance / faulty connection in the earth/ground path to the ECU or leading to the ECU.
Code:
Address 01: Engine Labels: None
Control Module Part Number: 06A 906 032 FT
Component and/or Version: 1.8l 5VT NB MT G 3996
Software Coding: 00001
Work Shop Code: WSC 00066
Additional Info: WVWZZZ9CZ2M604011 VWZ5Z0Z5141333
VCID: 75EBCB5E4FA118E9CA-515E
2 Faults Found:
17987 - Throttle Actuator (J338)
P1579 - 35-00 - Adaptation Not Started
17069 - ECM Power Relay Control Circuit
P0685 - 35-00 - Open Circuit
Readiness: 0110 1101Wiki suggests:
Possible Causes:
Voltage supply issue for ECM
Faulty ECM Relay (J271)
Possible Solutions:
Test voltage supply to ECM
Check wiring and fuses
Replace Faulty ECM Relay (J271)
As mentioned previously, measuring at the ECU harness (with the ECU out and IGN on or off):
T121/1 GND ok
T121/2 GND ok
T121/3 +12v ok via 15a Fuse 29
I've checked, cleaned and re-seated all the 3-main GND points in the plenum chamber, one of which is next to the ECU itself. Plus, the other couple of GND points in the engine bay - one with the Coil Pack harness by the coils and the other below the left side headlight near the air-box.
The only other GND point that I can think that 'may' have some bearing is the one on the IGN switch housing.. but I suspect that's ok as I have power to everything with IGN on.
I can work if a wire(s) has a break or relay is faulty etc etc... but this has really got me stumped.. Not sure where else to look ?
Last edited:
and would really appreciate some help here..
) - my engine code is AWU ! 
