Guru's Help please. A5 BRM Engine speed sensor, ECU & grounds

i am having the same problem as everyone, oil light flashing, glow plug light, car turned off wouldn't restart. it was raining hard and i was in the hwy, next day started right up...
scanned and had G28 engine speed sensor. cleared the code and hasn't come back. looked at the wiring harness under the air box and have some exposed wires. do i need to pull the battery as well and check under there?

Why not just start with fixing the exposed wires instead of looking for more trouble? That alone may fix your problem. One step at a time...

Ya that's where I am going to start and see if that's the fix.

zembu said:

Why not just start with fixing the exposed wires instead of looking for more trouble? That alone may fix your problem. One step at a time...

Click to expand...

Having similar issue on a 04 Passat BHW. I did a crankshaft replacement and car currently will start for 1-2 seconds then die. VCDS showing G28. Have a fair amount of wire insulation pulled back, but have not touched the 3 wire enclosed crankshaft sensor wiring. Ran good before crankshaft replacement and checked the pickup wheel verifying it matched damaged crankshaft. I swapped with a known good crankshaft sensor. Have continuity between ecu connector and crank sensor plug.

Next I would like to verify signal at those locations, but my labscope is out of commission at the moment.

when you say "VCDS showing G28, does that mean you triggering a code for G28?

Does Vagcom show a rpm reading as you crank the engine? Did you do the crank by removing the engine or did you do it in car?

Point being did you have a bunch of stuff unplugged when you did the crank?

And it takes a lot of either vacuuming the outlet line to pull fuel into the header/injectors or you have to crank for about 40 seconds to get the system full of fuel.

I would also verify that you are not getting the immobilizer to activate. That 2 seconds sounds as if it could be the immobilizer.

Hi everyone, it seems that I am experiencing the same problem. After an engine wash, the car turns off by itself, starts only after cranking for 3-4 seconds. on the dash, tach stopped working, and both oil light and glow plug lights are flashing. The code reader shows an engine speed sensor code P0726.

I read somewhere on this forum that it is an easy fix by checking and soldering the harness that goes to the speed sensor.

Please is there someone who can share a photo of the location of the harness/sensor.

Thanks in advance

Check my photo album.

loom under airbox

I recently took my 2006 jetta tdi on 8k trip. several times during the trip the engine would stumble and stop for a millisecond. Then the car completely stopped doing it for the last 3,000 kms. A search lead me to this thread so I decided to look at the loom under the airbox. Sure enough it has several similar issues although not as severe as others have found. Suprising considering the 325kms on my car. I have five wires that need to be repaired, none are broken but all five have worn through the plastic wire insulation in multiple places. It looks to me the greatest chafing occurs where the loom is held by the black plastic connectors.
A couple of questions: When replacing damaged wire is it necessary to solder the connections or is twisting the wire and shrink wrapping sufficient? The closest gauge wire I could get locally is 20 Gauge- is that acceptable to use? Did others remove the harness to repair or repair it in place?

Go for it!

20 gauge wire is fine.
I did it in place - no need to take it apart.
I twisted and shrink-taped mine.
Still going strong!

Use a Western Union splice with adhesive lined shrink wrap tubing.

Same issues here in IL. 249K miles

I have the same issues here in Northern IL. I have had the power steering light flash on and off repeatedly for years. I tried tightening the ground points to eliminate. Usually only occurred during wet times or at the change of seasons.

Yesterday I was driving along at about 65 mph, and the oil pressure started to flash along with the glow plugs and the loss of the ECS and cruise control. Bad timing as it was during a freezing rain storm.

Thanks to the forum, I was able to locate several worn spots in the harness under the air box. I spliced them with butt connectors and am using liquid electrical tape to seal the connectors. I am going to try using silicone tape to seal the harness.

One big issue I found by looking is that the positive cable to the starter was rubbing on the negative cable from the battery and had worn the negative through the insulation to the cable. If they had shorted the battery, who knows what would have happened. Glad I did some looking on my own.

Hopefully this will fix the issues, if not, I plan to get a new harness and install it. I did file a report with the NTSB today.

Good job. A battery explosion is a bad day. Glad you found the issues.

I read this thread with great interest.
My original code was for CTS G62, so I installed a sensor on my 05.5 Jetta BRM, but didn't check the pigtail. That didn't solve the problem, so I decided to check the grounds in the engine compartment. All the grounds I found looked good, but I cleaned them anyway and reinstalled them. I still have the code for the CTS, but now have a bunch of new codes. EGR(P0403), boost pressure regulation(P0234), MAF(P0102), and the both rad fans are running on full speed when the key is on.
Is it possible that I aggravated a chafe while working on the grounds?
Does the harness in that location carry wires for those components?
Thanks.

I would inspect the harness where it exits the frame rail near the transmission.

Inspection requires careful dissection of the split loom and tape, while looking closely at the wires. Also, rotating the wires a little will allow for better inspection.

Reassembly requires more tape, and possibly replacing that section of split loom.

Tony

TonyJetta said:

Inspection requires careful dissection of the split loom and tape, while looking closely at the wires. Also, rotating the wires a little will allow for better inspection.

Click to expand...

I agree with that. This thread has good information.
Does the wiring for those components run in that location?
Thanks.

I've got a customer car (2005.5 Jetta BRM) that has the P0322 code-Engine Speed Sensor-No Signal. It's doing the same thing as most others are experiencing with this intermittent fault---flashing glow plug light, no tach, low oil pressure indicator etc.

I opened up the wiring harness from the frame rail to the engine speed sensor and saw no signs of chafing at all. Also wiggled the harness while the car was running and everything was working fine. With that, I determined that the engine speed sensor was indeed faulty. I had already removed the oil filter housing/oil cooler to check the wiring to the speed sensor so I looked with a mirror to see what type/size of the bolt that holds the speed sensor. It was kind of rusty around the bolt, so I could not determine if it was a torx or a metric allen bolt. Also wondering how easy the sensor comes out, if I get the bolt out.

So, I have a couple of questions:

1. What size and type of bolt hold that sensor?
2. How common is it for the engine speed sensor to be faulty?

Thanks in advance, for any replies.

Just wanted to thank everyone for there input and info on this tread, My wifes 2006 TDI started having these problems last week, glow light flashing, oil light, kicked her out of cruise control, tack stop working , would stall at lights , but start right back up. So unwrapped the wire harness and only found two wires with wear marks in the wire insulation, at first it did not look bad, but with car running all i had to do was just touch this wire and it would kill the engine, so I cut out the bad piece and soldered in a new piece,All the wire strands inside were all broken, I rewrapped the wires in 3 groups, then all together, replaced everything , and all seems go so far.
The wire was the small blackone with red stripe , WHAT is this wire for ???[

Just looking back, and someone listed wire color, sounds like the black/red goes to the crank sensor.

Wow, this thread is still fixing cars, I would have thought most are in the bone yard by now.

sp55 said:

I've got a customer car (2005.5 Jetta BRM) that has the P0322 code-Engine Speed Sensor-No Signal. It's doing the same thing as most others are experiencing with this intermittent fault---flashing glow plug light, no tach, low oil pressure indicator etc.

I opened up the wiring harness from the frame rail to the engine speed sensor and saw no signs of chafing at all. Also wiggled the harness while the car was running and everything was working fine. With that, I determined that the engine speed sensor was indeed faulty. I had already removed the oil filter housing/oil cooler to check the wiring to the speed sensor so I looked with a mirror to see what type/size of the bolt that holds the speed sensor. It was kind of rusty around the bolt, so I could not determine if it was a torx or a metric allen bolt. Also wondering how easy the sensor comes out, if I get the bolt out.

So, I have a couple of questions:

1. What size and type of bolt hold that sensor?
2. How common is it for the engine speed sensor to be faulty?

Thanks in advance, for any replies.

Click to expand...

1) 6 mm Allen wrench
2 ) sounds like its not common.

I too , did not think it was my wire harness, but with car running and then move each wire I found the one that was broken off ( Black /red strip )

i know pretty much all the info you need is on here but i just fixed my 06 jetta tdi by doing what everyone said to do. i took some pictures and am going to show exactly where my problem was and how easy it was to fix. for some reason my wires had coolant build up in them and none of them were touching but the coolant acted as a conductor and made everything shut down. my problem existed right in front of my fan as seen in the pic. i simply cleaned and wrapped up the individual wires and than electrical taped the rest of them together, nothing fancy.

the best advice about this problem is like someone said before, hook up your battery and start puling or pushing around your wire bundles. this is how i found where my problem was. i should of done this to start because it would of saved me a lot of time. as soon as i touched the wires in front of my fan my car turned off.

i cant post a pic unless i give it a url. but my problem was right in front of the fan with 2-3 wires that had been indented and had some small amounts of wire showing. they werent thats bad but i believe the coolant and the bare wire spots got it to mess up.

You may want to search up "Coolant Migration" and rule that out.

I have read every post in this thread and I think I might actually have a speed sensor failure.



my car is a 05 Mk IV PD TDI, and the car starts perfect, every time, idles, drives, is totally normal, all the way till it reaches operation temperature then 1-5 minutes after that it shuts off.



cycle the key, the glow plug light starts to flash and VAG-COM shows no speed signal while cranking. let it sit 5-10 minutes, fires right back up and runs fine till it hits that 75-76 degree C then does the same thing. has never thrown a check engine light while doing this and the OBD2 system actually shows ready!!



vag-com says no signal from crank angle sensor, and a glow plug #3 fault.


my question is, I called VW and they could not find a part number for the speed sensor, does anyone here happen to have the part number?


as an interesting side note, I purchased this car is 2006 after it was was bought back by VW for random no start, they replaced the "front harness" and then auctioned the car. It has had 130K more miles put on it since then, with just normal maintance and repair.

AFAIK, Speed sensor on the A5 is through the ABS @ each wheel. Previous generations actually had a sensor in the trans.


Tony

Same G28 issue. 05/2006 build Mk5 Jetta TDI with 1.9 PD TDI BRM and DSG.

000802 - Engine Speed Sensor (G28)
P0322 - 000 - No Signal - Intermittent
Freeze Frame:
Fault Status: 00110000
Fault Priority: 0
Fault Frequency: 15
Reset counter: 255
Mileage: 448702 km
Time Indication: 0
Date: 2000.00.00
Time: 22:26:45

Freeze Frame:
RPM: 903 /min
Speed: 31.0 km/h
Load: 16.9 %
Voltage: 14.67 V
Bin. Bits: 00001000
Idle Stabilization: 0.0°KW
RPM: 441 /min

Intermittent issue occurring more and more frequently. Pulled airbox and repaired frayed red/black and purple above starter and issue improved, but still happens occasionally. Brown/blue looked fine.

When heat-shrinking, I accidentally melted through what appears to be a fiber core center of the loom at that point. Can I safely ignore this or was it some sort of conductive shield?

Will pull the battery box next to check wires under there...

Embarrassed to say I spent most of the weekend on this, again, with no luck. Could my intermittent issue actually be the G28 crank speed sensor itself? Can those fail intermittently? Which type is it (Hall, etc.)? Issue sometimes occurs over bumps or around corners, but also when idling and stationary (especially in stop and go traffic where it then stalls). Rarely if ever on a straight flat open road.

I've had the harness apart at least half a dozen times over the past several weekends, and this G28 induced limp mode issue is delaying my overdue cam and other maintenance. Found the tell-tale corrugated chafing pattern in half a dozen wires including both the red/black and purple wires at the starter clamp and the first engine clamp. Replaced those wire sections one of which apparently solved issue of fan always on but still having the G28 issue. Wires that run under battery showed no damage at all (which is to be expected since those were wrapped in cloth-backed tape without troublesome corrugated sheath). Just bypassed all three of the red/black, purple and brown/blue from about 6 inches from speed sensor all the way back to battery tray, but still with no improvement.

I guess I have to either bite the bullet and replace the harness or the speed sensor itself. Not sure what the dealer gets for a new harness, but I saw a used one for $100 or so or I suppose I could start scouring the bone-yards. Thoughts?


EDIT:

Bob S. said:

... the speed sensor shows that it was superceeded ...

Click to expand...

Anyone know the correct part number for the updated version on BRM? I take it it's the single-piece plastic sensor with integral connector for BRM, rather than the sensor with wire to connector as must have been on BEW and BHW. Is 045906433A the correct part # for BRM?

Add me to the list of people fixed after reading this thread. I unwrapped the harness and saw no bare-wire type damage anywhere. I did see insulation chafing but not all the way through.

I was at the end of my rope so I figured I'd throw $300 at it and replace the harness.

I also took apart every ground I could find, polished all of the connectors then reassembled with bulb grease.

Between those two ^ the problem went away and hasn't come back. Unfortunately I'm not sure which fixed the car because I did all of it at the same time.

I've ordered two different G28 ESS sensors online that were advertised as HENKO, but I'm beginning to suspect poor knock-offs as both have had locking ramps about 0.070" too far from the harness connector's locking tab (versus my original sensor as well as both my original and the replacement harnesses), preventing the connector from properly locking on. I guess my original sensor was made by FAE (per one of the pictures below). I've modified one purported HENKO sensor to physically fit (barely), but unfortunately that one doesn't work electrically (perhaps I damaged it if I over-stressed it the first time by pushing on the connector that simply would not click on before I eventually modified the sensor by both shortening the near end of its socket and grinding off the farther half of its locking ramp). My original sensor is the lighter colored FAE sensor in the pictures below, and it generally starts the car quickly but cuts out too often. Has anyone else run into this issue of non-fitting sensors? I did consider removing the internal harness connector seal to see if that would help, but then thought better of that since it can get wet down there.

When I checked ETKA 7.2 for my 2006.5 BRM, I read the part number for the G28 ESS of 036906433A. But someone else posted 036906433E in this thread. I called my local VW dealer and they said 036906433E is, in fact, a superseding number for 036906433A, but that either should fit the BRM engine.

Someone posted the wrong size for the G28 ESS sensor's Allen bolt in this thread. It's actually 4mm, and an extended ball-end wrench is required to get at it via the harness access opening (possible but tedious with a long L-wrench, easier with a long socket bit) after removing at least the oil cooler. I beleive the only way to get at it with a short and/or non-ball-end 4mm allen would be to pull the trans and align the flywheel to where there's a clearance notch for presumably this purpose. Having had my sensor out four times already, I ended up making such a socket by modifying a 4mm ball-end Allen and jamming it into an old 5/32 broken-tip socket with side retention screw. Snap-on actually sells one pre-made. Of my four removals so far, 1st removal = oil cooler off with L-wrench (VERY tedious); 2nd removal = oil filter housing off with L-wrench, 3rd removal = oil cooler off with socketed long 4mm (much faster), 4th removal = everything in place and socketed 4mm (even faster, but it was a VERY tight fit and I was NOT able to repeat this feat on a different car).

For those wanting another data point as to how common the harness wire chafing issue is, whether or not coupled with or causing a damaged G28 (a.k.a. engine speed sensor (ESS) or crankshaft position sensor (CPS) or impulse sensor), I've had the opportunity to check well over two dozen 2006 Mk5 Jetta BRM harnesses in Canadian junkyards this summer, and all but one had badly chafed wires and/or obvious prior harness repairs (that one presumably having had a recent harness replacement, which now lives on in my car). I think many of these get junked in winter, as the extended cranking before ECU fallback from crank sensor to cam sensor drains the battery before it would have otherwise started in warmer weather.



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