Probably my first post on here, I've had a good search around trying to find a solution but I cannot come up with much.

Purchased a 2001 1.4TDI. Just had it in for its MOT and it ended with 11 failures. I spent the following days replacing all brake lines, ball joints, CV joints, stupid HID lights and LED bulbs and a rear wheel bearing.

The last thing to do is the ABS light. This has been on since I purchased the car with the previous owner telling me it was just a simple sensor.

I have read the codes, and he was right, it points to the front right sensor (00285), I have changed this. Driven it, cleared codes, still there.

So today I went to check the fuses, heard about fuses blowing in the engine bay causing issues. They're all good, as is fuse 8 in the box inside the car.

MOT man said probably speed ring, I've cleaned that up this morning back to metal in the hope the corrosion would be causing it. Again no fix. Instead it threw out another error code.

I already have a few errors that need resolving, the MAF and boost pressure sensors have codes. There is also an alternator code that is coming up.

These are the ones I had after a test drive:

• 18057/P1649/005705 - Powertrain Data Bus: Missing Message from ABS Controller (Cleared and this went away)
• 17964/P1556 - Charge Pressure Control: Negative Deviation (Fairly sure this relates to the fact it had been remapped, only happens under load)
• 17911/P1503 - Load signal from Alternator Term. DF: Range/Performance / Implausible Signal (Is this related?)
• 16485/P0101/000257 - Mass Air Flow Sensor (G70): Implausible Signal (New MAF needed)

And from the ABS module:

• 00285 - ABS Wheel Speed Sensor Front Right (G45) (Replaced sensor)
• 00668 - Supply Voltage Terminal 30 (??)

All but 00285 will clear. Does anyone have a wiring diagram so I can test the wiring to the sensor and hope that isn't broken. The next step is obviously a new speed ring, don't really want to change the whole bearing if I don't have too. Looks like it will need a press out?

I'm starting to lose the will with it. Any more suggestions?

First Welcome to the forum.

00668 is low battery voltage (30 is Battery voltage, 15 is Ignition supply, 50 is Start supply) The battery fuses often "look" OK but they only need a bit of a crack or corrosion on them to give this low battery voltage code

Here's the wiring diagram of the sensors

Thanks man, so what I thought - the alternator may be the cause, or more likely, the fact the fuse box does not have a lid and the terminals inside look corroded.

I did a continuity test on each fuse and they appear to be working fine. I will double check later though.

I really dislike Polo ownership thus far.

The Alternator load code wont have caused the ABS codes, check the thin Blue wire from the alternator, as they are prone to failure in the plastic conduit

You're probably right. It was a broken wire behind the rubbed boot. Wen to cut out the corroded section and had to take it right into the connector. That was all broken too.

Still failed it's mot though. Headlight adjusters have snapped, bowls held in with cardboard. What a joke.