- Jan 24, 2012
- Golden, CO
- 96 Passat B4V, ALH engine out of a 2002 Jetta, some IE Rods and ASV Pistons. Nothing drivable yet though
The ALH has three versions.My next conundrum is Glow Plug wiring. I have been doing a lot of reading on the various different ways to do it. I would very much like to retain the glow plug system that is already integrated in the CE2 fuse box....I literally just got glanced at a wiring diagram and I think it may be much easier than I thought it would be. Since I am using an 03 Jetta ECU which uses a feed back loop to ECU pins 33 and 9. Is it possible to just leave those pins unplugged and call it good? It seems like that would be something that can be tuned out if a DTC is thrown.
This can also be seen here on tracks 60 and 64 (96 jetta) and the GP light part of it here track 62 on a early ALH.Relay pin ST - ECM to relay. ECM uses this wire to activate the relay when specified conditions are met where the glow plugs are to be on. 5v signal. White/purple wire. ECM pin T80/42.
Relay pin D1 - 5v signal back to ECM when ST pin is powered. This circuit provides feedback to the ECM that includes fault checking. Green wire. ECM pin T80/37
There are differences between 00/01 and 02/03 in the wiring diagram the MAP sensor for example is different. The 00/01 has a loop back and a trigger wire for the GP relay. All that is needed is the trigger wire and turn off the DTCs for the missing loop back. All ALH ECUs have K29 and K83 outputs - same pins for mid and late ECUs. Both also do K29 and K83 over CAN as well, so the CAN2DASH unit I sell works for all EDC15 ECUs and it capable of driving a 5W lights or LEDs correctly if that's what you are looking at doing. It also has a tachometer output that is directly compatible with the MK2 coil based tachometer as well - just so that you can keep you options open!More GP questions!
It seems like there is a ECU feedback loop from the old style GP to the ECU as explained here. Essentially with the 80 pin ECU...
This can also be seen here on tracks 60 and 64 (96 jetta) and the GP light part of it here track 62 on a early ALH.
So my questions are these.
Which pins are which for the 121 pin ECU? Based on the 03 Jetta (tracks 19 and 20) and from what I assume is an earlier than 03 golf based on pin differences, specifically ECU pin 42 (older golf) and ECU pin 9 (newer jetta).
In the earlier ALH diagram pin 41 goes to the GP light which I believe would equate to g2/5 in the AHU diagram. Both later diagrams show pin 41 as empty HOWEVER, pin 40 in both diagrams HAPPENS to be bl/gn. Since the newer ALHs use CAN bus for GP signal, do you think it would be an accurate assumption that the GP light on the later ALH ECUs can come from pin 40? If not which wire in the newer ALH is the feed forward ECU to GPR (D1:G1/3) and feedback GPR +5V/Glow Plug Light (ST:G2/5)?
Okay so it's just a matter of sw and I can remove the "smart glow plug" from the system.
Edit: so i was incorrect it was the CEL pin that may be non-funtional in the later 121 ecm'sIf Im correct the 02 and 03 ECUs with the 4 wire glow plugs are the same, at least it seems that way based on what I gather from MrDave.