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Audi A4 2002 and later, S4 2004 and later, RS4 2007 and later (B6) B6 S4 4.2L Cam Adjuster Open Circuit Faults - Engine runs but not driveable

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Last Post: Oct 22, 2009 3:44 PM Last Post By: Audinauts
Audinauts

Posts: 54
Registered: 07/15/05
B6 S4 4.2L Cam Adjuster Open Circuit Faults - Engine runs but not driveable
Posted: Sep 12, 2009 6:55 PM
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I have a 2004 S4 4.2 Liter with chain drive cams BHF engine code. It has recurring faults P1536 and P1528 (open ciruits) for both camshaft adjusters. I can erase the DTCs and they will not return until starting engine, at which point engine runs terrible and the DTCs return within 30 seconds. I haven't come across this before and was wondering if anyone else has, or any insight into this

17944 - Camshaft Timing Adj. Bank2 (N208): Open Circuit
P1536 - 004 - No Signal/Communication - MIL ON
17936 - Camshaft Timing Adj. Bank1 (N205): Open Circuit
P1528 - 004 - No Signal/Communication - MIL ON
Audinauts

Posts: 54
Registered: 07/15/05
Re: B6 S4 4.2L Cam Adjuster Open Circuit Faults - Engine runs but not driveable
Posted: Oct 3, 2009 2:48 AM   in response to: Audinauts in response to: Audinauts
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Throttle Body reports DTC's and suspect causing very rough idle, limited throttle response and car not drivable. Disconnect Throttle Body 6 pin electrical connector results in immediate smoother idle engine and reduced mechanical noise in intake when engine warm. Can try replace ECU Power Relay J271 per periodic P0688 DTC

Thoughts ?

Address 01: Engine
Control Module PN: 8E0 910 560 A HW: 8E0 907 560
Component and/or Version: 4.2L V8/5V G 0020
Software Coding: 0007711
Work Shop Code: WSC x

6 Faults Found:

17973 - Throttle Actuator (J338): Lower Stop not Reached
P1565 - 008 - Implausible Signal

17972 - Throttle Actuator (J338): Under-Voltage during Basic Setting
P1564 - 002 - Lower Limit Exceeded

17072 - ECM Power Relay Load Circuit: (J271): Open Circuit
P0688 - 004 - No Signal/Communication

17944 - Camshaft Timing Adj. Bank2 (N208): Open Circuit
P1536 - 004 - No Signal/Communication

17936 - Camshaft Timing Adj. Bank1 (N205): Open Circuit
P1528 - 004 - No Signal/Communication

19475 - Valve for Exhaust Flap 1 (N321): Open Circuit
P3019 - 004 - No Signal/Communication - Intermittent

Readiness: 0110 1101
Bresha

Posts: 415
Registered: 02/23/09
Re: B6 S4 4.2L Cam Adjuster Open Circuit Faults - Engine runs but not driveable
Posted: Oct 3, 2009 6:38 PM   in response to: Audinauts in response to: Audinauts
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For issues with throttle body module would suggest to clean throttle body and clean terminals, battery condition must be satisfactory in order to set throttle adaptation 01 engine electronics, 04 basic setting and 060 for adaptation.
Before adaptation and if the battery ok would do capacity discharge for about thirty min.
For cam. adjuster faults and exhaust flap valve would suggest to get the wiring diagram and check the wires to those components, they might have something in common, either ground or power supply.
If not already would replace ECM power supply relay, common failure on VW and Audi's. Good luck.
BTW, what's the mileage on your vehicle?

Bresha
Audinauts

Posts: 54
Registered: 07/15/05
Re: B6 S4 4.2L Cam Adjuster Open Circuit Faults - Engine runs but not driveable
Posted: Oct 6, 2009 1:40 PM   in response to: Bresha in response to: Bresha
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Thank you for the reply Bresha

Mileage is ~165K KM. Battery measures good. Capacitive discharge at battery terminals completed. Battery and TB contact connections are clean. Ohmed 6 wires from TB connector to ECU connector and all are good. Measure "ign on" voltage at TB connector pins per Bentley Manual and they pass. Still Throttle Body reports ERROR in VAG when attempting adaption and therfore unable to adapt, repeatedly attempted with same result.

New ECM Power Relay will arrive in a few days and will try that as next step.
Bresha

Posts: 415
Registered: 02/23/09
Re: B6 S4 4.2L Cam Adjuster Open Circuit Faults - Engine runs but not driveable
Posted: Oct 6, 2009 8:23 PM   in response to: Audinauts in response to: Audinauts
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Hate to say this but we looking here at faulty throttle body if all we discussed previously checked out ok. I was able to save a few by removing the plastic side cover and you'll see some connection similar with the relays if you ever took one apart. What i did on those is to use 1000 sand paper and clean those connection really gently and you'll see two sliding connection (depends on design) i cleaned those with the contact cleaner (do not use sand paper on those)and right after used shop air to blow out any excessive cleaner residue or to dry it out. It worked for me, you can try also. Good luck.

Bresha

P.S.
How did you determine battery condition? load test or just the voltage measurement?
Audinauts

Posts: 54
Registered: 07/15/05
Re: B6 S4 4.2L Cam Adjuster Open Circuit Faults - Engine runs but not driveable
Posted: Oct 10, 2009 12:28 PM   in response to: Bresha in response to: Bresha
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Replaced Relay J271 with brand new OEM unit.

Disassembled TB and cleaned internals as per your excellent recommendation. Applied high quality electric contact cleaner on circuit board resistive traces plus clean two contact blades for TB motor. This one previous recurring DTC no longer returns so one issue appears solved:

17973 - Throttle Actuator (J338): Lower Stop not Reached
P1565 - 008 - Implausible Signal

Next try TBA but still Alignment not possible due to ERROR reported in VAG. Tried two year old Ross Tech KEY-COM cable and brand new HEX-USB-CAN Ross-Tech cable with two different laptops & latest VAG COM version = same result. Can hear normal faint high pitch TB sounds when attmpting TBA. Manual move throttle plate reports expected TB position sweep in VAG so TB TPS's appear operational. Again tested TB wire harness 6 pins to ECU connector and continuity passes including test for no shorts between TB 6 wires.

The plot now thickens. Borrowed same pinout operational Throttle Body from a perfect running B5 A4 1.8T and connected to B6 S4 Throttle Body electrical connector and TBA reports ERROR and unable to align. Then performed TBA using B6 S4 TB on operational A4 vehicle and successful with no DTC's, including seeing normal TB Plate open and close by pressing A4 gas pedal. Conclude S4 TB is OK. Then original ECU Code copied and flashed into OEM remanufactured identical B6 S4 Engine ECU including dealer coded for Immobilizer and no change meaning same returning DTC's and TBA not possible.

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

Clear all DTCs, do not attempt to start engine and scan reports 1 DTC:

1 Fault Found:

17972 - Throttle Actuator (J338): Under-Voltage during Basic Setting
P1564 - 002 - Lower Limit Exceeded

Attempt to start engine (cranks and may or may not start) then scan reports more DTCs:

5 Faults Found:

17972 - Throttle Actuator (J338): Under-Voltage during Basic Setting
P1564 - 002 - Lower Limit Exceeded

17072 - ECM Power Relay Load Circuit: (J271): Open Circuit
P0688 - 004 - No Signal/Communication

17944 - Camshaft Timing Adj. Bank2 (N208): Open Circuit
P1536 - 004 - No Signal/Communication

17936 - Camshaft Timing Adj. Bank1 (N205): Open Circuit
P1528 - 004 - No Signal/Communication

19475 - Valve for Exhaust Flap 1 (N321): Open Circuit
P3019 - 004 - No Signal/Communication - Intermittent

Abnormal mechanical noise inside intake & exhaust flap constant actuating becomes increasingly noticable while idling engine is warmed to operating temp.

Battery voltage was tested and passed but not load tested. Lowest voltage observed (other than when cranking) was 11.85 volts but this was after many cranking attempts. Tried 1 hour capacitive discharge again and trickle charged battery for a day yielded no change.

Cleaned grounds on upper middle Firewall and under ABS Pump on chassis with no change.

Continuing to study Wiring Diagrams.

Thoughts?
gemini

Posts: 155
Registered: 07/07/04
Re: B6 S4 4.2L Cam Adjuster Open Circuit Faults - Engine runs but not driveable
Posted: Oct 21, 2009 7:28 PM   in response to: Audinauts in response to: Audinauts
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"original ECU Code copied and flashed into OEM remanufactured identical B6 S4 Engine ECU including dealer coded for Immobilizer"

- Just to be clear, you swapped the B6's ECU with a new one?
Also, I dont believe the B5 and B6 TBs are two way, reverse interchangeable. Even though they might pin out.
- Out of curiosity, what is the AC voltage produced at idle? Ive seen AC voltage leaks that make the wildest things happen.

  • And, last but not least, did these problems happen all at once? Or maybe after a service on the vehicle?
Audinauts

Posts: 54
Registered: 07/15/05
Re: B6 S4 4.2L Cam Adjuster Open Circuit Faults - Engine runs but not driveable
Posted: Oct 22, 2009 12:04 PM   in response to: gemini in response to: gemini
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Yes, we purchased an Audi remanufactured last alpha "AX" replacement ECU and shipped S4 to local dealer. Dealer copied vehicle parameters from original ECU to new ECU including immobilizer info. Upon vehicle return, both ECU's report same faults during all tests. Software version is the same "0020" in both ECU's.

Yes B5 and B6 TB's are not the same but electically they appear to operate the same. When connected B6 TB to B5 car, we can perform successful VAG TBA and visually see B6 TB Plate move normally in sync with B5 gas pedal & B5 vehicle VAG scan reports no TB errors. Connect known working B5 TB to B6 S4 and same VAG "Error" reported when attempting to perform TBA as with B6 TB. This leads us to believe B6 S4 TB is OK but open to all input.

Can you please clarify where we should measure AC Voltage at idle?

These problems happened all at once. A VAG Scan this past July showed misfire on Cyl 5, that coil pack had failed and was replaced. The only service attempted after latest drivability problem appeared and before we worked on vehicle was six of eight coil packs replaced with new OEM ones yielding no change.

We still wonder why J271 relay still causing same DTC after replacing with new J271 relay.

We connected two brand new Cam Adjusters and same CA DTC's appear. They both noticably produce audible buzz at idle.

We are wondering if stray AC (from where?) causing TB Faults, yet this still does not explain very rough idle even with TB 6 pin disconnected. We will do compression test next. Is it possible a cam chain gear at back of engine has spun out of time / cause Cam Adjuster DTC's as possible out of compensation range and therefore report generic "Open Circuit" DTC's?
gemini

Posts: 155
Registered: 07/07/04
Re: B6 S4 4.2L Cam Adjuster Open Circuit Faults - Engine runs but not driveable
Posted: Oct 22, 2009 3:12 PM   in response to: Audinauts in response to: Audinauts
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"We connected two brand new Cam Adjusters and same CA DTC's appear."
- Have you checked the voltage going to them? Also, remember, the Cam Adjusters are different than the Cam Postion Sensors.

"They both noticeably produce audible buzz at idle.....Is it possible a cam chain gear at back of engine has spun out of time / cause Cam Adjuster DTC's as possible out of compensation range and therefore report generic "Open Circuit" DTC's?"
- Possibly, however one would expect some other codes as well. If its currently apart, check the marks, also the chain links for proper spacing. Refer to your Bentley manual.... Hows the oil look as well?

"We are wondering if stray AC (from where?) causing TB Faults, yet this still does not explain very rough idle even with TB 6 pin disconnected."

- You bet your butt it could. Leaking AC voltage is very rare, but when it happens, you would kick yourself in the head knowing that all you had to do was start with the basics.... Real simple, just use a GOOD quality DVOM (multi meter) and switch it to AC NOT DC voltage. Test at the battery at idle, different rpms, and with loads on and off.... Excessive AC voltage from the alternator is poison for DC electrical system..... It will take just a few minuets to test, and im not saying thats your problem, but its a good practice to start doing.

Keep us posted with the compression test results, also the AC readings. Good luck. - Evan
Audinauts

Posts: 54
Registered: 07/15/05
Re: B6 S4 4.2L Cam Adjuster Open Circuit Faults - Engine runs but not driveable
Posted: Oct 22, 2009 3:44 PM   in response to: gemini in response to: gemini
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Yes confirm we tested with new Cam Adjusters and not CPS's. We electrically connected new Cam Adjusters and did not physically install them. All 4 CA coils (original two and new two) all measure 11 ohms cold. We did measure Cam Adjuster DC voltage and it's good, along with ohming Cam Adjuster and TB wire harnesses which also ohm within spec.

Excellent point regarding stray AC. I have a 20Mhz Oscilliscope and a hand held meter. Will check at battery for AC riding on 12V DC.

Also interesting to note that both Cam Adjuster Open Circuit DTC's appear immediately as soon as engine starts, yet when TB 6 pin is disconnected then it takes several minutes idling for same CA DTC's to appear.

Will do more tests this weekend and report.

Thanks!
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