Common OBD-II Problems

OBD-II has now been in our faces for a "Quarter Century" and even though it works fairly efficiently to control the hydro-carbon emissions in post '96 vehicles to some degree, it isn't as effective as some people would've liked, in terms of its diagnostic accuracy or as transparent and simplistic in its use to aid the layman.  On the flip side, many people with several mechanics among them completely abhors OBD-II and sees it more as a hindrance that a help and even add that they prefer cars not to have OBD-II. Since its inception, OBD-II has stymied mechanics globally, especially when the OBD-II system shuts down the engine and turns on the  EPC Light or Check Engine Light. And today, some 25 years later most car owners and mechanics still suffer fits effects yet endure the wrath of OBD-II. However, regardless of what we as lay people say, OBD-II is here to stay and we cannot wish it or will it away. 

Genuine Volkswagen / Audi Harness Mfg Part #: 1KD971658

Personally I think OBD-II is a great in all aspects and incarnations however it has its drawbacks. OBD-II  does place car owners at a huge disadvantage and at risk when it fails. Purely because the problems are not evident but rather masked by the mysteries of electronics technology. This very often leaves them stranded and in a dangerous situations when stuck in the middle of nowhere. With the result that even the DIY car owners cannot do any repair work themselves, but have to resort to phoning  a salvage company to come  load their vehicle onto  a rollback.  Unless of course they have previously invested in a OBD-II scanner  and is able to check for DTC error codes.  But as the saying goes, "most people only lock the stable after the horse has bolted". 

Another drawback of OBD-II is that since car owners in general do not own diagnostic scanners; so they have to rely on some mechanic workshop or mechanical to tell them what problems they've encountered with their vehicle but only once its repaired. Considering most mechanics / repair shops repair OBD-II errors by substituting parts until the cause of the problem is  solved. Merely because they don't even understand the workings of OBD-II well enough to pinpoint problems with any great success. For most of us, this type of hit-&-miss approach comes as an un-bugeted expense, which most car owners can ill-afford especially after having to pay the exorbitant rollback cost.

I believe there are thousands more vehicle owners today, interested in their own vehicle's maintenance and there are even more inclined towards DIY repairs than ever before because of ODB-II. Their motivating factor being the high cost of automotive repairs vs the low cost of ODB-II diagnostic scanners. Albeit that the lower cost scanners bordering on cheap doesn't do such a fantastic diagnostic scan as their more expensive counter parts. 

NEW GENERATION CARS

Hopefully, the next generation of automobiles will be released with onboard diagnostic scanners incorporated directly into the vehicle's infotainment system. Seeing that these fancy units are comprised of  several discrete devices built into the same platform.  It's quite common for the average touch screen infotainment systems to have features ranging from  Built-in Bluetooth to Built-in WIFI which supports WiFi hot-spot broadcasting. Integrated phone connectivity for calls. Some even have rear view camera support. 

Others have fully fledged full-format 1080P video decoding, and USB functionality with multi-format audio and multi-band radio, coupled to dedicated dual voice-coil subwoofer and surround sound speakers. Not to mention Internet APP download capability.  Some include mirror and link for both Android and IOS Phones and a Global Positioning System (GPS) for navigation. All thanks to the magic of powerful multi-core processors and microprocessor embedded systems. 

I'd say adding an OBD-II scanner in place of one of these gadgets would be more beneficial 

So, throwing in a pretty decent quality OBD-II scanner into such a menagerie of tech wouldn't be such a biggie for car manufacturers and the cost wouldn't be prohibitively expensive either.  But since we not at that point in automotive evolution as yet, most DIY car owners have to rely on the handheld / smartphone diagnostics to scan their cars. 

Be that as it may. Very fortunately there are some common fault lists that would prevent you from having to go buy an expensive OBD-II scanner or go through the agony and trauma of having your car fixed by trial and error. Sharing  common automotive problems for the benefit of other, who are bound to experience the exact same problems in the very near future is a godsend.  Same model cars tend to have the same problems as others but invariable and inevitably those components will fail because obsolescence was part of its initial design. The same components used different model cars tend to fail in the same way and cause the same problems.

We've found that the most common OBD-II problems are associated with misfiring engine cylinders, problematic exhaust Gate Reticulation system (EGR), Oxygen Sensor (O2), Electrical Harnesses and fault Catalytic Converters. Many car owners are decating their diesel models, claiming better performance. But since OBD-II was explicitly introduced to control and reduce carbon emissions, removing it is not such a great idea. 

VW / Audi Harness ES#: ES2993475  

 

COMMON FAULTS 

Erratically idling, or misfiring of bucking or  car goes into limp mode or starts and cuts out all result any one or more of the following error codes:-

P0105 - Manifold Absolute Pressure / Barometric Pressure Voltage supply

P0106 - Manifold Absolute Pressure / Barometric Pressure out of range 

P0107 - Manifold Absolute Pressure / Barometric Pressure Low Input

P0108 - Manifold Absolute Pressure / Barometric Pressure High Input

P0234 - Turbocharger Overboost Condition Control limit exceeded

P0235 - Turbocharger Boost Sensor (A) Control circuit  limit not reached

P0236 - Turbocharger Boost Sensor (A) circuit  out of range

P0237 - Turbocharger Boost Sensor (A) circuit  Low Input

P0238 - Turbocharger Boost Sensor (A) circuit  High Input

P0243 - Turbocharger Wastegate Solenoid (A) Open/Short Circuit to Ground

P0245 - Turbocharger Wastegate Solenoid (A) Low Input/Short to ground

P0246 - Turbocharger Wastegate Solenoid (A) High Input/Short to B+

P1154 - Manifold Switch Over Malfunction

P1155 - Manifold Absolute Pressure Sensor Circuit Short to B+

P1156 - Manifold Absolute Pressure Sensor Circuit Open/Short to Ground

P1157 - Manifold Absolute Pressure Sensor Circuit Power Supply Malfunction

P1158 - Manifold Absolute Pressure Sensor Circuit  out of range

P1400 - EGR Valve Circuit  Electrical Malfunction

P1401 - EGR Valve Circuit  Short to Ground

P1402 - EGR Valve Circuit  Short to B+

P1403 - EGR Flow Deviation

P1404 - EGR Flow Basic Setting not carried out

P1406 - EGR Temperature Sensor Performance range

P1407 - EGR Temperature Sensor Signal too Low

P1408 - EGR Temperature Sensor Signal too High

P1511 - Intake Manifold Changeover Valve - Electrical circuit malfunction

P1512 - Intake Manifold Changeover Valve Short circuit to B+

P1513 - Intake Manifold Changeover Valve2 Short circuit to B+

P1514 - Intake Manifold Changeover Valve2 Short circuit to ground

P1515 - Intake Manifold Changeover Valve Short circuit to ground

P1516 - Intake Manifold Changeover Valve - Open circuit 

P1520 - Intake Manifold Changeover Valve2 - Open circuit 

P1521 - Intake Manifold Changeover Valve2 electrical circuit malfunction

P1553 - Barometric/manifold pressure signal ratio out of range

Polo Highline 1.9 TDI (9N) 2005

16621 - Manifold Pressure / Boost Sensor (G31): Signal too Low

P0237 - 000 - -

Audi A5 (8T0) 2012 

4166 - Manifold Pressure / Boost Sensor (G31)

P0238 00 [039] - Signal too High

Audi TT 1.8L R4/5VT 

16622 - Manifold Pressure / Boost Sensor (G31): Signal too High

0238 - 35-00 - 

000568 - Manifold Pressure / Boost Sensor (G31): Signal too High

P0238 - 001 - Upper Limit Exceeded - MIL ON

Passat 2.0T R4/4V TFSI 2006 

000568 - Manifold Pressure / Boost Sensor (G31): Signal too High

P0238 - 001 - Upper Limit Exceeded - MIL ON

VW Touran 1.9 TDI

P0236 - Manifold Pressure/Boost Sensor (G31) - Range/Performance Problem/Implausible Signal

Malfunction Indicator Lamp (MIL)(K83) active.

VW Golf 7 1.6TDI 

16622 (P0238 ) - Manifold Pressure/Boost Sensor (G31): Signal too High

16618 (P0234) - Boost Pressure Regulation: Limit Exceeded (Overboost Condition)

Passat 2.0T R4/4V TFSI 2006 

004759 - Pressure Drop between Turbo and Throttle Valve

P1297 - 001 - Upper Limit Exceeded

This MAP Manifold Pressure Sensor aka Boost Sensor aka Thrust sensor  aka G31 is just a  thermistor. Essentially a resistor of a special kind, with the ability to change its resistance  subject to its surrounding temperature, hence the term thermistor is just a  word combination of "thermal" and "resistor".  However G31 sensor may not be fault but rather the wiring harness. Due to the constant engine heat, the harness wiring gets hard and becomes brittle resulting in poor contact, short and open circuits. 

FYI - Thermistors essentially come in two varieties, viz NTC (negative temperature coefficient) and a PTC (positive temperature coefficient). You can quite simply use an ohmmeter to measure the resistance of the thermistor. Then by bringing a hot soldering iron  tip close to the thermistor, its resistance would change in response to the soldering iron's radiated heat. When the resistance increases its a PTC and an NTC when the resistance decreases.  Much like discrete component resistors that are colour coded, thermistors leads are also colour coded which identifies the temperature range they operate at.

CATALYTIC CONVERTER

Catalytic Converter have become a hot topic of late. Thieves are stealing Catalytic converters from parked cars at night. However the Polo Highline 1.9 TDI is known to be troublesome. The main reason for  this being, use of poor quality diesel (500ppm as opposed to 50ppm or even 5ppm) and irregular oil changes  which caused soot build-up to block the performance of the catalytic converter, which in turn may lead to turbo failure.  So its fair to say that it's  not uncommon to remove/replace blocked catalytic converters  to prolong the life of the turbo itself.

However if it's not the Catalytic converter itself causing the above error,  it very possibly not the sensor either even though the diagnostic software may indicate that.  I'd say rather check, repair or replace the wiring harness to the Boost Pressure Sensor (G31) and also check wiring to the Intake Air Temperature Sensor (G42).  See my previous blog post https://volkswagen-polo-highline.blogspot.com/2015/03/wiring-harness-issues.html 

The diagnostic scanners may also thow the following errors in conjunction with the error above,  which could be caused by a leak in Air Intake and or Exhaust

16490 - Manifold / Barometric Pressure Sensor (G71) / (F96): Implausible Signal

P0106 - 35-00 - -

18000 - Altitude Sensor / Boost Pressure Sensor: Implausible Correlation

P1592 - 000 - -

Diesel engines are quite different from petrol engines in the sense that  the diesel engine is not variable in speed or power by controlling the air entering the engine as we do with the  throttle body in petrol styled engines. Feedback from Catalytic converter in petrol engines are also used to adjust the short term and long term fuel trim. Implying that petrol cars also have turbo boost errors due to the cat and intake and exhaust sensors.

16485 / P0101 Mass Air Flow Sensor (MAF) (G70) = Circuit Signal Implausible (out of range)

16497 / P0113 Intake Air Temperature  Sensor-1 (G42) = Signal too High

16515 / P0131 O2 (Lambda) sensor low voltage =  Bank-1 Low Voltage

16584 / P0200 Injector circuit =   Injector Circuit electrical fault

16620 / P0236 Turbo / Manifold Pressure Boost Sensor (G31) = Signal Implausible (out of range)

16622 / P0238 Turbo / Manifold Pressure Boost Sensor (G31) = Signal too High

16683 / P0299 Turbo Boost Pressure Reg = Control Range not reached (underboost) /mechanical fault

16785 / P0401 Exhaust Gas Recirculation (EGR) = Insufficient Flow (blocked)

17055 / P0671  Glow Plug/Heater Cylinder 1 (Q10)  electrical fault, open circuit 

17958 / P1550 code = Charge Pressure Control Deviation

Check for air leaks on both intake or exhaust side 

Turbocharger - check for whining engine and exhaust smoke

Charge Air Pressure Sensor faulty  - check connection to one of the the intercooler pipes

Wastegate Regulator N75 Valve  faulty  - Check one of the 3 thin hoses for leaks

18534 / P2102 Throttle  Actuator Control Motor = Signal too Low, check voltage to accelerator pedal 

18675 / P2243 O2  Sensor Reference Voltage Bank 1, open circuit 

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