I'm looking for some info or a wiring diagram to help me trace the pulse wire for the rev counter on my 2001 Polo SDi,

Any help would be most appreciated.....

Do you know the engine code? as it looks like it's sent from the engine ECU on the canbus wires

Thanks for the swift reply Nige,

Its an ASX mate.

Ok,

Speed sensor pin 1 to three pin connector pin 1 White wire (Black) on left of engine to pin 102 on ECU

Speed sensor pin 2 to three pin connector pin 2 Yellow wire(Black) on left of engine to pin 110 on ECU

Speed sensor pin 3 to three pin connector pin 3 Black wire (Black) on left of engine to Ground

Signal out from ECU pin 27 Green/Blue wire to 10 pin connector (under relay panel (Red) pin 10 to pin 11 of Blue plug on Speedo

Your a godsend Nige thanks so much....

Hi Nige, would it be possible to help me out with a wiring diagram for a polo SDi (engine code ASX)? I have a non starter at the mo & have done the following:

 

-replaced the relay 109, no change.

-tried another ECU with the matching Immo ECU, no change.

-cleaned up a few earth points but not the ones behind the N/S headlight because the bumper needs removing for access, planning to do this at some point if needs be but would like to check the ECU has power & ground.

 

Symptoms are, engine cranks ok but no glow lamp, and will not start. I would like to check from the ignition barrel through to the ECU hence, needing a wiring diagram but in the first instance, checking the power & ground wires at the ECU plug/s.

 

Any help would be very much appreciated.

 

Many thanks

 

 

 

 

Edited 28 April, 20215 yr by MK1Derv

The glow light doesn't come on on most SDI's unless it's actually using them. Have you tried taking the stop solenoid out and removing the plunger?

Thanks for the response. Is the stop solenoid electronically controlled via the ecu or immo? I'll take a look at it to see it its being powered in the first instance.

Forgot to mention, i have a fault code from the instrument cluster - 01314 engine control module 49-00 no communications. This is what's led me to believe the ecu is either not powered or theres a CANbus issue.

Also just realised that i've asked nige a question based on a post from 2014 so apologies for that.

 

If anyone can help me with a wiring diagram it would help massively.

The main grounds are on pins 4 & 5 of the ECU via the ground stud in the plenum chamber area, there is also a ground on pin 86 but that is a ground for the screened cables for a couple of sensors and that is shown as "left side engine bay" so not vital and certainly not the cause of your non starting.

 

The 15 supply (Ign ON) is via relay J491 (airbag crash relay ) and then via fuse #32 to pin 37 ECU (J491 position is not shown on the wiring diagrams ? but if you find it you could try bridging pins 4 & 8 as they are the main contacts to supply pin 37 )

 

The 30 supply (battery live) is via J317 (30 supply relay) then via fuse #37 to pins 1 & 2 ECU (again no location shown for J317 ??)

You truly are the legend I've been reading about! Thanks for the details, that's absolutely perfect. Could I be cheeky & ask for an image of the schematic too or would you mind sending it me direct?

 

Many thanks

9 hours ago, MK1Derv said:

Could I be cheeky & ask for an image of the schematic too or would you mind sending it me direct?

 

Many thanks

 

There are 11 pages for just the engine wiring diagrams and my scanner isn't playing ball at the moment so I can't print them out and scan them 

No worries Nige, really appreciate the info you've provided.  Checked the two relays tonight with the first being relay 405 which i think is j491 (airbag crash relay). Removed the relay and bridged the pins as you suggested and it started! 

 

Plugged the relay back in and decided to see which other relay may prevent the glow lamp coming on and give the same non start symptom and as suspected, removing relay 109 prevented the lamp from coming on and engine cranking only. I can only assume that relay 109 is j317.

 

The final thing i've identified is that when i had refitted both relays, the glow lamp came on and the engine started which suggests that relay 405 has not completely failed but is becoming unreliable. Bizarre thing is that the engine has not failed to start since plugging it back in but i'm planning to buy a new one for peace of mind.

 

In summary, if either relays 109 or 405 fail then the non start and no glow symptoms are what to expect on an X reg (2001) polo sdi. 

 

Gonna run it for a week or so when the new relay comes so fingers crossed, i wont be needing the the ecu kit i bought (ecu, dash, immo ecu, steering column with ignition barrel)

 

If anyone needs that kit, please let me know.

 

Many thanks for your help Nige!

On 28/04/2021 at 18:02, Yeti said:

The glow light doesn't come on on most SDI's unless it's actually using them. Have you tried taking the stop solenoid out and removing the plunger?

 

It's just a 12v ignition switched circuit. You can test the feed voltage with a light on the ring terminal on top (the wires prone to damage), and a vcds scan will give an indication of it's working, but pulling it out and removing the plunger is a pretty standard diagnostic step on old diesels.

 

There's only about 6 things ever stop an SDI from starting:

 

Flat battery

Fuel pump relay (feel for the relay dropping/tap it with a coin/bridge it out)

Ignition switch contacts (work the key in and out as you turn it)

Stop valve (pull the plunger out)

Stop valve wiring (visual check/drop 12v to the ring terminal/test light check)

Broken cambelt

 

If they're all good, I'd go as far as to say the engine will almost always start and run to some extent.