P0113 CAYC MK6 Golf Intake Air Temp (have VW ordered me the right part?)

[paul b]

Update: Had the ECU checked by BBA-Reman, no faults found and unit returned. Fitted a new Haldex pump (I noticed the earth strap on the old pump had broken), but still no comms.

Visually checked fuse s22 - OK.

I checked there is power at the plug. My pin 2 was not brown, it was orange/black. Pin 7 was brown, a check across pins 1 and 7 shows 12.4V. Across pins 1 and 2 shows approx 10v.

I'm a bit lost at the moment - Any advice?

[Crasher]

I would be fitting a new ECU 0AY 907 554 J and keeping my fingers crossed I wasn’t binning £601.20 but often I have no choice. Last week I nearly screwed up on Mrs Crashers Polo 9N3 GTI, the ABS, ESP and brake warning kept going off randomly with voltage errors common on the BOSCH pump used. I looked to ACTronics for a repair but the codes stored were specifically listed as unrepairable so I looked at ordering a new unit at £1470 but there was no UK stock of the revised unit. The battery was obviously weak (ANOTHER Varta failure after only six months) so I ordered a Bosch S5 (made in the same factory as Varta owned by JCB, yes, really) but with it out I decided to pin to the ECU and check the three feeds, perfect continuity. I noticed the fuses on the battery were a bit dirty so decided to clean them, I released the M6 nuts, washed them down with contact cleaner and blew them dry with the air line at which point fuse 4 (ABS main power) jumped apart into two and then fell back together with a break invisible to the naked eye and when checked, still showing continuity across the studs… a £1500 **** up avoided.

[paul b]

Thanks for the info, Crasher. In light of your info, I'll try to load-test the circuit and verify some kind of comms on the powertrain CAN hi & low wires. Then I should know that all is OK up to the Haldex controller. If all that checks out OK then I suppose a new ECU might have to be the next step. Thanks for your support!

[paul b]

Just in case anyone reads this in future:
- Load test of power to the Haldex connector - verified OK.
- Ground checked
- Can HI & LO check - 2.2V on L, 2.8V on H which I understand is a plausible reading.

There was a fifth wire on the connector whose function I'm uncertain of. It was 0V with engine-off.

I think I've convinced myself the Haldex ECU is faulty.

[paul b]

Just to bring closure for anyone reading in future.
This pin is very important:

There was a fifth wire on the connector whose function I'm uncertain of. It was 0V with engine-off.

It is ONE of TWO power feeds to the Haldex (gen 5) ECU. This one (pin 3) is an (ignition) switched live. And so the lack of voltage turned out to be the problem. Fuse SC16 had blown.

Pin out of 8 pin connector:
1 - Permanent live (fuse SC18), purple/black
2 - CAN Lo, yellow/brown
3 - Switched live (fuse SC16), red/white
4 - CAN Hi, yellow/black
5 - unused
6 - unused
7 - Ground, brown
8 - unused

Some Internet folklore has you believe pin 3 is a brake light or handbrake switch input to the Haldex ECU. This is not true, at least on Haldex Gen 5 in a 2014 Facelift Skoda Yeti 4x4.

[Roverfan]

Just to bring closure for anyone reading in future.
This pin is very important:

It is ONE of TWO power feeds to the Haldex (gen 5) ECU. This one (pin 3) is an (ignition) switched live. And so the lack of voltage turned out to be the problem. Fuse SC16 had blown.

Pin out of 8 pin connector:
1 - Permanent live (fuse SC18), purple/black
2 - CAN Lo, yellow/brown
3 - Switched live (fuse SC16), red/white
4 - CAN Hi, yellow/black
5 - unused
6 - unused
7 - Ground, brown
8 - unused

Some Internet folklore has you believe pin 3 is a brake light or handbrake switch input to the Haldex ECU. This is not true, at least on Haldex Gen 5 in a 2014 Facelift Skoda Yeti 4x4.

Thanks, I drive a cayc too. Question is what is Haldex?

[Crasher]

The rear drive coupling on 4Motion models

[Crasher]

Some Internet folklore has you believe pin 3 is a brake light or handbrake switch input to the Haldex ECU. This is not true, at least on Haldex Gen 5 in a 2014 Facelift Skoda Yeti 4x4.

The VAG diagram show pin 3 as unused with the connector T6s being "6-pin connector, on fuel tank, left", I searched right through the diagram and T6s/3 is not shown connected to anything but black/red colour coding suggest line 15 ignition power.