2008 Jetta 000802 - Engine Speed Sensor (G28) Fault

[Skezza]

Morning,

Was driving home the other day and my normally extremely reliable 1.9 tdi Jetta decided to throw a bit of a wobbler. I had probably done 70 or 80 miles by this point, but various lights started flashing on the cluster including the glow plug, the oil light and various warnings on the little screen including
Low Oil Pressure
Emissions Garage
STOP!

I stopped the car and it wouldn't restart. I sat waiting for an hour for breakdown before trying it again and all of a sudden it restarted, so I was able to safely get home. However, I took it for a spin to town yesterday and it did the same thing again. This time I noticed that the car actually doesn't cut out, although it does feel a bit lumpy. Again, it started fine again after a period of being left parked.

This is what a scan has shown:

39365

Will this be as simple as just replacing that sensor?

[Crasher]

There is nothing simple about changing that sensor, they are a pig! I had this on a DPF BMN engined Golf 5 a few months ago and it was damaged wiring up near the turbo.

[Skezza]

There is nothing simple about changing that sensor, they are a pig! I had this on a DPF BMN engined Golf 5 a few months ago and it was damaged wiring up near the turbo.

That's not good news at all. Based on the failure case, is it likely to be damaged wiring or the sensor itself?

Tempted to just take it my local garage tbh. I was hoping it'd be an easy win, I had not taken a look at the actual complexity of replacing it :(

[Skezza]

So I've just driven it again paying close attention to the temp gauge.

Heat is definitely playing a part. The first time it occurred it was at normal running temp, the second time I had been driving for 15 mins.

Today I watched the temp go all the way to 12 o clock and then it did it again.

That makes me think sensor over wiring.

Reasonable jump?

[Crasher]

It is unusual for the G28 to come up as faulty. We have a Q5 in today from another garage who have fitted a new G28 and it still comes up and it has been to lots of other people including Audi... In this particular case I know that water in the EGR cooler on the back of the head (from an internal leak) causes this code as it upsets the 5V circuit for various sensor of which the G28 is one and the most sensitive; when my tech pulled the plug off there was pink coolant inside the plug.

[Skezza]

So I've driven home from work tonight. Happened again... different failure case.

Whereas this morning it happened just as the temps hit 12 o clock but the car kept running to work... This time the car hit 10 o clock on the temp gauge, the issue occurred and the car died literally while I was doing 30mph.

I had the heater on full blast and left it for 30 seconds. Car started again but was lumpy as hell and flashing lights all the way home. Luckily only a mile.

So for time being, it's a kids to school car lol.

Any thoughts on the above? Is it sounding more like what you describe?

[Skezza]

Driven it to drop children off at school this morning. Car didn't get fully warm (about 2 miles). Issue didn't occur.

[Crasher]

Does sound like the G28.

[Skezza]

Does sound like the G28.
OK, so the car has just come back from the garage. They said there's a 4 week wait on the Crank sensor and therefore they won't be able to get it fixed for a while. However, they've also said they think there's a bigger problem with it. They think there's an electrical wiring fault because various lights come on including:
Traction Control
Oil Pressure
Glow Plug

They're not wrong that those lights come on, I'm just curious if this is what usually happens when said sensor packs up? Any thoughts?

I've been driving this because I have no other vehicle. What's the risk if I continue to drive it (other than it constantly cutting out in inconvenient situations)?

[Crasher]

What is the VIN and the fault code numbers?

[Skezza]

What is the VIN and the fault code numbers?
I've scanned it again and it's now got a different fault code on the engine:
VIN: WVWZZZ1KZ7M178797 License Plate:
Mileage: 198430km-123298mi Repair Order:



--------------------------------------------------------------------------------
--------------------------------------------------------------------------------


Chassis Type: 1K (1K0)
Scan: 01 03 08 09 15 16 17 19 25 42 44 46 52 56 62 72 76

VIN: WVWZZZ1KZ7M178797 Mileage: 198430km-123298miles

00-Steering Angle Sensor -- Status: OK 0000
01-Engine -- Status: Malfunction 0010
03-ABS Brakes -- Status: Malfunction 0010
08-Auto HVAC -- Status: OK 0000
09-Cent. Elect. -- Status: Malfunction 0010
15-Airbags -- Status: Malfunction 0010
16-Steering wheel -- Status: Malfunction 0010
17-Instruments -- Status: OK 0000
19-CAN Gateway -- Status: Malfunction 0010
25-Immobilizer -- Status: Malfunction 0010
42-Door Elect, Driver -- Status: Malfunction 0010
44-Steering Assist -- Status: Malfunction 0010
46-Central Conv. -- Status: OK 0000
52-Door Elect, Pass. -- Status: OK 0000
56-Radio -- Status: Malfunction 1010
62-Door, Rear Left -- Status: OK 0000
72-Door, Rear Right -- Status: OK 0000
76-Park Assist -- Status: OK 0000

-------------------------------------------------------------------------------
Address 01: Engine Labels: 03G-906-016-BKC.clb
Part No SW: 03G 906 021 KH HW: 03G 906 021 AN
Component: R4 1,9L EDC G000SG 9245
Revision: --H06--- Serial number: VWZ7Z0G9070756
Coding: 0000071
Shop #: WSC 00066 000 00000
VCID: 6FECEB207E9D0D3CF1-803A

1 Fault Found:
000802 - Knock Sensor 1 (G61)
P0322 - 000 - Malfunction - Intermittent
Freeze Frame:
Fault Status: 00110000
Fault Priority: 0
Fault Frequency: 18
Reset counter: 255
Mileage: 198248 km
Time Indication: 0
Date: 2000.00.00
Time: 08:29:37

Freeze Frame:
RPM: 840 /min
Voltage: 2.15 V
(no units): 12.0
Temperature: 4759.2°C
Bin. Bits: 00101100
Load: 261.2 %

Readiness: 0 1 0 0 0

I've left all of the other fault codes out for now.

[Crasher]

VAG UK have 52 speed sensors in stock, part number 036 906 433 E and Euro Car Parts have 864 in stock so someone is feeding you Bovine Excrement. There is something strange going on though, a BXE engine does knot have a G61 knock sensor...

[Skezza]

VAG UK have 52 speed sensors in stock, part number 036 906 433 E and Euro Car Parts have 864 in stock so someone is feeding you Bovine Excrement. There is something strange going on though, a BXE engine does knot have a G61 knock sensor...
Understood.

How would you proceed? I can take it another garage, a VW specialist? I can run it into the ground as a "car to work" and no further only? Or I can bang it spares repair on Gumtree and move it on?

[Skezza]

Quick update, drove it again tonight. Issue occurred again, however I did notice something different tonight. When the issue first occurred, the car seemed to lose power. It was as if the turbo couldn't boost, for about 20-30 seconds. I've noticed that if I'm going above about 20-30mph, the car bump starts itself back into life after the fault. I continued to drive and after about 30 seconds, it was as if the car was fine, but had blackpool lights on the dashboard. I captured some further diagnostics.

What's with the voltages.... 2.5v? 7v?

Driving to destination (fault occurred)

-------------------------------------------------------------------------------
Address 01: Engine Labels: 03G-906-016-BKC.clb
Part No SW: 03G 906 021 KH HW: 03G 906 021 AN
Component: R4 1,9L EDC G000SG 9245
Revision: --H06--- Serial number: VWZ7Z0G9070756
Coding: 0000071
Shop #: WSC 00066 000 00000
VCID: 6FECEB207E9D0D3CF1-803A


1 Fault Found:
000802 - Engine Speed Sensor (G28)
P0322 - 000 - No Signal - MIL ON
Freeze Frame:
Fault Status: 11100000
Fault Priority: 0
Fault Frequency: 19
Reset counter: 255
Mileage: 198248 km
Time Indication: 0
Date: 2000.00.00
Time: 08:29:37


Freeze Frame:
RPM: 840 /min
Voltage: 2.15 V
(no units): 12.0
Temperature: 4759.2°C
Bin. Bits: 00101100
Load: 261.2 %


Readiness: 0 1 0 0 0

I then cleared the faults for the trip home. The issue reoccurred.


-------------------------------------------------------------------------------
Address 01: Engine Labels: 03G-906-016-BKC.clb
Part No SW: 03G 906 021 KH HW: 03G 906 021 AN
Component: R4 1,9L EDC G000SG 9245
Revision: --H06--- Serial number: VWZ7Z0G9070756
Coding: 0000071
Shop #: WSC 00066 000 00000
VCID: 6FECEB207E9D0D3CF1-803A


2 Faults Found:
000802 - Knock Sensor 1 (G61)
P0322 - 000 - Malfunction - MIL ON
Freeze Frame:
Fault Status: 11100000
Fault Priority: 0
Fault Frequency: 20
Reset counter: 255
Mileage: 198248 km
Time Indication: 0
Date: 2000.00.00
Time: 08:29:37


Freeze Frame:
RPM: 840 /min
Voltage: 2.15 V
(no units): 12.0
Temperature: 4759.2°C
Bin. Bits: 00101100
Load: 261.2 %


005520 - Altitude Adaptation
P1590 - 000 - Signal Out of Tolerance - Intermittent
Freeze Frame:
Fault Status: 00100000
Fault Priority: 0
Fault Frequency: 1
Reset counter: 255
Mileage: 198471 km
Time Indication: 0
Date: 2000.00.00
Time: 21:30:45


Freeze Frame:
RPM: 0 /min
Voltage: 7.01 V
Mass Air / Rev.: 318.8 mg/str
Mass Air / Rev.: 10.0 mg/str
Bin. Bits: 00011010


Readiness: 1 1 0 0 0

However, there are other fault codes logged and some of them look bizarre. Here are a few:

01312 - Transmission Control Module
008 - Implausible Signal - Intermittent

The car is a manual.


02384 - Telephone Mount (R126)
009 - Open or Short to Ground

Doesn't have one.

Address 16: Steering wheel Labels: 1K0-953-549-MY8.lbl
Part No SW: 1K0 953 549 AP HW: 1K0 953 549 AP
Component: Lenksäulenmodul 636 0070
Coding: 0000041
Shop #: WSC 00066 000 00000
VCID: 000EB89C5303024418-8054


1 Fault Found:
01395 - Signal Conductor for Central Locking; Doors Open
014 - Defective - Intermittent

^ ?! Door definitely wasn't open and why is that under steering wheel...

01305 - Control Module for Roof Electronics (J528)
004 - No Signal/Communication - Intermittent

Definitely doesn't have any roof electronics.

03072 - Parallel Parking Assistance Control Module (J791)
004 - No Signal/Communication

On a 2008 Jetta?

03200 - Switch for Electric Parking Brake (E538)
012 - Electrical Fault in Circuit - MIL ON

It has a normal handbrake.


I tried to do some measurements:
21:42:54
924 /min Engine Speed (G28)
903 /min Engine Speed (G28)
0.0 Accel. Pedal Pos. Sensor 1 (G79)
945 /min Engine Speed (G28)
51088.0 Exhaust Gas Recirculat. (actual)
62.05 ms Exhaust Gas Recirc. Duty Cycle
924 /min Engine Speed (G28)
924 /min Engine Speed (G28)
0.0 Accel. Pedal Pos. Sensor 1 (G79)
0.5 °BTDC Intake Air Temperature (G72)
4.3 °ATDC Coolant Temperature (G62)

Seems the engine speed sensor is working OK. This was post-fault conditions.

I'm now wondering if I've got a defective ECU... That's my only explanation as it stands.

[Crasher]

Could be the ECU but I am more inclined to think a wiring problem. You need a VAG specialist who knows what they are doing or cares which I get the feeling the last one didn't

[Skezza]

Thanks. I've reached out to a VW specialist. Let's see what they say.

Do you know what kind of wiring faults are common with this car? I'm not all that handy with the mechanical side of stuff but I'm pretty good when it comes to car wiring, if I know where I'm looking. If there's somewhere to start, I can take a look.

One last thing to note, under View Readiness, Exhaust Gas Recirculation reads:

Failed or Incomplete.

The rest is fine.

[Crasher]

There is wiring around the turbo at the back of the head which can get damaged by heat but that tends to be cars with DPF, BMM 140PS and BMN 170PS engines. The G28 can get upset by all sorts, the other week we had a Q5 come in which had been to three other garages and had three G28's, the last one being Audi Nottingham. I knew straight where to look, put it in the air went to the back of the engine, unplugged the EGR valve and coolant poured out the plug. The EA189 EGR cooler leaks coolant into the motor and plug which spikes the G28 signal as it, and others, uses the same 5v power supply. If it is left for a long time, say it hasn't upset the G28, the coolant gets forced all the way back to the ECU up the tiny gaps in the cores of the wiring so you unplug the ECU and the connector is full of coolant as is the ECU and FUBAR!

[Skezza]

There is wiring around the turbo at the back of the head which can get damaged by heat but that tends to be cars with DPF, BMM 140PS and BMN 170PS engines. The G28 can get upset by all sorts, the other week we had a Q5 come in which had been to three other garages and had three G28's, the last one being Audi Nottingham. I knew straight where to look, put it in the air went to the back of the engine, unplugged the EGR valve and coolant poured out the plug. The EA189 EGR cooler leaks coolant into the motor and plug which spikes the G28 signal as it, and others, uses the same 5v power supply. If it is left for a long time, say it hasn't upset the G28, the coolant gets forced all the way back to the ECU up the tiny gaps in the cores of the wiring so you unplug the ECU and the connector is full of coolant as is the ECU and FUBAR!
My car definitely does not have a DPF. Would the EGR cooler issue you've just mentioned likely result in View Readiness, Exhaust Gas Recirculation saying Failed or Incomplete?

My current thoughts are that I'm going to see what I can do myself before taking it to the VW specialist who have quoted me £105 per hour to investigate. Ultimately, it seems that I can get where I need to go most days... it's just a bit rough and £105 an hour could get expensive rather quickly. These things are a rabbit hole.

I'll take a look at the wiring around the back of the turbo with what limited access I have sans ripping everything off... The other thing I'm wondering is, I can buy a BXE 1.9TDI ECU off eBay to see if there's an ECU issue. It would need me to clone the EEPROM from my current ECU (luckily something I've done once or twice before) but might be a way of ruling out an ECU fault?

[Crasher]

I have only seen it on engines with electrically operated EGR valves and the G28 is direct to ECU on the BXE. A new/used ECU is not plug and play, it has to be coded to the car (easy with VCDS) but matched to the immobilser in the instruments which isn't easy without ODIS or specialist aftermarket gear.

[Skezza]

I have only seen it on engines with electrically operated EGR valves and the G28 is direct to ECU on the BXE. A new/used ECU is not plug and play, it has to be coded to the car (easy with VCDS) but matched to the immobilser in the instruments which isn't easy without ODIS or specialist aftermarket gear.
Luckily, this is an area that I have some experience in. I don't usually pair the immo, opting to either clone / swap the EEPROM from the existing ECU or simply doing an IMMO OFF on the donor instead. Certainly on EDC15 and ME7.5 I've previously been able to extract the SKC as well which allows a proper pairing job. I know it all sounds very janky, but would help me avoid the whole ODIS / Abrites route. If I take it the specialists and it's the ECU, it's going to come back via the Abrites / ODIS route regardless and I know from experience that turns into £££.

Is there any risk if I plug a non-paired ECU and then plug the original ECU back in? I'm sure I've heard some VAG cars it can send the Instruments into a sad brick-like place (I'm thinking Audi with an RB8 cluster) and can leave the car in a non-start state.

[Crasher]

If you clone it there should be no issue, I had to last week with an A4 TDI as my ODIS laptop's wifi failed so I just cloned a used ECU instead of using ODIS.

[Skezza]

Understood. Thanks mate.

If i plugged in the ECU without clone, is there any risk of bricking the cluster? Just weighing up my options as while I've done many a hot air SMD removal, there's always a first time it could go wrong hence preferring an IMMO OFF first (but they're not 100% first time usually).

[Crasher]

I prefer ODIS reprogramming, I have had a couple of cars brick themselves after an ECU change but not irrecoverably.

[Skezza]

I prefer ODIS reprogramming, I have had a couple of cars brick themselves after an ECU change but not irrecoverably.
I've ordered the ECU. Going to clone the EEPROM in the first instance and just fire it up. See if the issue persists. I suspect it'll run like dogs dinner at first but with it being for the same engine, I hope, touchwood, that it sorts itself.

I suppose what I could do is run it up to temp and subsequent failure conditions and then see if swapping the ECU then causes it to fix itself?

[Crasher]

Old ECU’s are becoming a serious PITA as I cannot find anyone I trust to properly check or repair them. I had one done by ACTronics a couple of weeks ago and they said there is nothing wrong with it but I am convinced they are wrong as whatever they did to it highlighted two definitely faults that were not visible before on THREE previous ECU’s one of which is definitely faulty. There is Bosch in Germany who will “recondition” it for €500 but what if I get the same result as they have let me down in the past.

[Skezza]

Old ECU’s are becoming a serious PITA as I cannot find anyone I trust to properly check or repair them. I had one done by ACTronics a couple of weeks ago and they said there is nothing wrong with it but I am convinced they are wrong as whatever they did to it highlighted two definitely faults that were not visible before on THREE previous ECU’s one of which is definitely faulty. There is Bosch in Germany who will “recondition” it for €500 but what if I get the same result as they have let me down in the past.
Well for this car, it'll probably be a death sentence if I can't repair it. I can't justify £110 per hour to a specialist. Electrical gremlins can be so difficult to track down. This is my lazy attempt. Fingers crossed I suppose.

[Skezza]

I'm back.

So, new ECU has arrived. I've IMMO OFF'd it, in the first instance, but might just clone the eeprom off the one in the car. Was a pain to get apart. It had some thermal compound I've not seen before that had welded... However I can't help but come back round to the idea that this might actually be the crank sensor. I wouldn't say I've done a whole lot of sleuthing here, but I decided to plug a little cheapie bluetooth OBD dongle and run torque while the issue occurred to see what was logged.

I must have cleared the code and let it trigger again about 10 times and the same fault was logged every time:
P0726 Engine Speed Input Circuit Range Performance

Searching for that code brings quite a few people who have experienced it, same engine, same symptoms (quite a few worse) and a good number of them saying a new crankshaft sensor did the trick. OEM only... don't go aftermarket.

I've also started to experience more of the symptoms you would experience with a failing crankshaft sensor, such as weird spluttering and bouncing forwards, stalling unexpectedly etc. It's also getting worse. Some days now the car won't start for a few mins after stalling.

I spoke to the original garage again and asked them for a flat quote on how much to replace the crank sensor? No further diagnosis.
They said something to the effect of
"£150 if we don't have to split the gearbox, £400 if we do and it all hangs on whether we can remove a single bolt. If we can't, it's a gearbox out job"

So I know very little about this bolt, but as I understand, it's behind the oil filter housing. What's the chances of it actually coming? Is it necessary to remove the gearbox?

Is this something I could do on my drive, realistically? I'm a moderate mechanic... can roughly find my way around, but definitely not garage material.

[Skezza]

Any thoughts @Crasher (https://www.vwaudiforum.co.uk/forum/member.php?u=6324) ?

I've noticed that there's no specific temperature that it fails. Sometimes it happens at 55 degrees, other times as high as 72 degrees.

Tbh, the running temp seems a tad low (only gets up to like 78 deg) but I don't think it's related.

[Skezza]

Back again.

Had a go at fitting new immo-off'd ECU today. Car absolutely would not start but logged yet again the same crank sensor error + a new one I've not seen: 005732 - PD Unit Injector; Cylinder 2. Guessing that's unrelated to the main issue though.

It logged nothing related to the immobilizer. No idea if it's a faulty ECU or just because I've not paired it in any way at all. Reinstalling the original ECU works, but obviously I'm letting it cool down before trying again.

Doing some reading up on that and will probably clone the EEPROM, especially if IMMO-OFF'ing hasn't worked :)