VCDS error code P0321: crankshaft position sensor

[new/used golf 2006]

hello.

this started with a problem getting smogged that i described here: https://forums.tdiclub.com/index.ph...m-problem-cant-pass-smog.535324/#post-5876781

possibly salient context:

• the car runs fine.
• no check-engine lights.
• the smog guy said the comprehensive control was reading as "not ready." he suggested it might be because i had recently change the battery. but i drove it around, and it didn't pass in three attempts.

a kind and generous member of the forum read the codes with his VCDS yesterday and found error code P0321. (details below.)

i'm looking into replacing the crankshaft position sensor.

does that sound like the right path forward? if so, is it something that a novice mechanic who can replace simple parts outside the engine is likely to be able to tackle?

thanks for any insights you care to share!

here is the reading from the VCDS:

Address 01: Engine Labels: 038-906-016-BEW.lbl
Control Module Part Number: 038 906 016 AG HW: 028 101 255 3
Component and/or Version: R4 1,9L EDC G000SG 7000
Software Coding: 0150031
Work Shop Code: WSC 00000 785 00200
VCID: 59EF8E69E503803270D-5184
1 Fault Found:

16705 - Engine Speed Sensor (G28)
P0321 - 000 - Implausible Signal
Freeze Frame:
RPM: 252 /min
Torque: 162.0 Nm
Speed: 0.0 km/h
Load: 0.0 %
Voltage: 8.36 V
Bin. Bits: 00001100
Idle Stabilization: 0.0°KW
RPM: 21 /min


Readiness: 0 0 1 0 0

 

[STDOUBT]

Did you try clearing the code? I'd at lest try that before spending money.
You could always make sure it and its wiring looks clean and intact.

 

[new/used golf 2006]

i got my hands on an obd scanner today and tried to clear all the codes. the ccm still shows up as "not ready."

i checked the wiring on it (thanks for the great tip, stdoubt), and it has no obvious defects.

i'm going to order a new one on monday and replace it when it arrives.

while the job looks pretty straightforward, i welcome any advice.

many thanks, everyone!

 

[Lex4TDI4Life]

Just a heads up, even once you clear the code, it will show as not ready for a while. There is a specific procedure for resetting readiness (you have to drive for a certain distance at certain RPMs) but I think if you just drive it long enough without the code coming back, it will show as ready. Once you replace the sensor, drive for a while and see if the readiness resets.

 

[new/used golf 2006]

when i took a look at the bolt holding the sensor in, i originally thought it had a hex head.

i just went in to remove it and discovered that it's a star head.

anyone happen to know what size?

 

[Mozambiquer]

when i took a look at the bolt holding the sensor in, i originally thought it had a hex head.

i just went in to remove it and discovered that it's a star head.

anyone happen to know what size?

They are often a 9mm 12 point head, though maybe 10mm. A regular 12 point socket works

 

[new/used golf 2006]

it was indeed a 9mm 12-point bolt.

i replaced the crank shaft position sensor. then i drove it about a hundred miles. then i checked it with an obd scanner. it still says "ccm not ready."

i suppose the problem could be in the wiring harness someplace after the spot where the csp sensor plugs in. but that harness is wrapped in a corrugated plastic sheath, and i don't see any obvious signs of wear.

what would you do next in the problem-solving process?

 

[P2B]

it was indeed a 9mm 12-point bolt.

i replaced the crank shaft position sensor. then i drove it about a hundred miles. then i checked it with an obd scanner. it still says "ccm not ready."

Did you clear the crankshaft position sensor code after replacing the sensor? Were any diagnostic codes set during the drive cycle?

 

[new/used golf 2006]

i suppose i could have performed the clear codes function with the scanner, but i didn't think to do it because it said "no codes" or something like that. (it was only when i went inside one of the menus that i discovered the message that said "ccm: not ready.")

as for the question about diagnostic codes set during the drive cycle, i don't know enough about all this to answer that question. i think the answer is no, since the scanner said "no codes." but maybe i'm misunderstanding. i don't know what the drive cycle is.

i'm sure it's frustrating to help someone with limited vocabulary and knowledge. i really appreciate your patience!

 

[P2B]

I suspect the scanner is not telling you the full story. If there really are no codes, I would expect a hundred miles would be sufficient to set readiness, but it's possible it just needs to be driven some more - perhaps to meet up with someone who has VCDS

 

[new/used golf 2006]

i'll give that a shot.

many thanks for all of these tips!

(i've been concerned that the ongoing ccm unreadiness may be a sign of an expensive problem in the actual crank shaft.)

 

[AndyBees]

i'll give that a shot.

many thanks for all of these tips!

(i've been concerned that the ongoing ccm unreadiness may be a sign of an expensive problem in the actual crank shaft.)

There is nothing about the crankshaft that could cause what you're experiencing with your engine.

I assume the BRM engine is basically the same as the ALH with respect to the Crankshaft Position Sensor.

There is a round plate (my words) at the rear of the crankshaft that has 4 notches in it. As the crankshaft rotates, the sensor picks up those blanks (notches). I suspect the sensor is magnetically operated, thus, when that blank spot rotates past the sensor a signal is generated.

In the photo below, one of the four notches can be seen on the right of the crankshaft. And, straight above and below the oil cooler you can see the wire going over to the Crankshaft Position Sensor.

 

[Vince Waldon]

(i've been concerned that the ongoing ccm unreadiness may be a sign of an expensive problem in the actual crank shaft.)

If one man's opinion helps you sleep better at night I'd tell you that IMHO the crankshaft is probably the most bullet-proof part of the entire engine. It happily survives missed shifts, hydrolocking, turbo runaways, dirty oil, 24:1 compression, and has no problem bending rods to its bidding.

I agree with the above: if you've not already done so a VAG-specific scanner may give you more of the story and give you a known good "clear all codes", you may still have a lingering issue with the crank position sensor system, or you may just need a bunch more miles of varied driving. The drive cycle required to set full readiness is a bit of a mysterious beast and can sometimes be a bit persnickety.

 

[new/used golf 2006]

thanks for the encouraging perspectives, vince and andy.

i'm determined to get to the bottom of this. with little time, less knowledge, and limited access to tools, it's become a saga.

thanks for the input and patience, everyone!

 

[AndyBees]

Sometimes it is a struggle and challenge with the knowledge and all the tools. Hang in there, You will solve the problem,

I'm somewhere in the middle trying to solve some Diagnostic Test Codes with the ALH TDI engine in my 84 Vanagon.

 

[P2B]

In many jurisdictions you can pass the emissions test with one monitor not ready provided the MIL/CEL is not illuminated. Is that not the case in CA?

 

[new/used golf 2006]

it seems to vary by smog station.

the state recognizes that computer problems shouldn't prevent you from passing, and they've set up a process to address this. but it's, as i mentioned, a process, so i avoided it.

if i'd gone that route at the outset it probably would have been easier than the path i've taken.

but at this point, the ccm readiness challenge has turned itself into a battle that i'm unwilling to lose.