Boost Press fault, ESP and Start Stop Fault and Limp Mode

[JohnK]

Hi all.

Odd problem with a Passat B7 1.6Tdi Bluemotion 2012.

Symptoms:

Traveling at a steady ~50 on a clear road.

Glowplug indicator started flashing and car went into limp mode.

Got to where we were going and restarted a few hours later: Car seemed fine.

Booked it in to be looked at. (Independent VW specialist)

He did an ODB scan and advised he saw “Low manifold pressure” (from memory) which suggested air leak in the intake system

He checked hoses, ducts and pipework and found no problem. Cleared the fault and a test drive didn’t throw it up again.

A few days later:

Waiting in queue at gas station. Space came clear and I rolled forward the last yard with clutch down, no brake needed and just canme to a stop at the pump.

Glowplug indicator started flashing, message on console display “ESP fault”, followed by “Start Stop fault” (From memory)

Fault cleared on restart

A few days later:

Going round roundabout gently (full  180 degree turn at small roundabout)

Glowplug indicator started flashing, message on console display “ESP fault”, followed by “Start Stop fault” (From memory)and car went into limp mode

Fault cleared on restart

Booked it in to be looked at again.

Had “Low voltage on boost sensor” (from memory)

Changed sensor, test drive without incident.

Going home later that day

Just driving along <20mph, Glowplug indicator started flashing, message on console display “ESP fault”, followed by “Start Stop fault” (From memory)and car went into limp mode

Back to garage and code scan still gave “Low voltage on boost sensor” (from memory)

Diagnostics advice for “ESP fault” and “Start Stop fault” suggest checking the engine management computer (which could implicate whatever caused the boost sensor fault)

We now wonder whether there is damaged wiring somewhere between the EMC and the boost sensor. The guy proposes to run new wiring and isolate old cables.

Small update: 

I have fault code p0237 stored.

 

Anyone have any ideas?

Many thanks

[Volkswagen Owners Club]

Hi JohnK..welcome to the forum

Here is some info on the code:

Quote

P0237 - Turbocharger/Supercharger Boost Sensor 'A' Circuit Low           Possible causes Boost pressure sensor harness is open or shorted Boost pressure sensor circuit poor electrical connection Faulty boost pressure sensor Faulty Turbo/Super Charger Engine over temperature Ignition misfire exceeds the calibrated threshold Faulty Knock sensor (KS)   What does this mean? When is the code detected? This diagnostic trouble code (DTC) P0237 will set if the boost pressure sensor signal is below the predicted range. Possible symptoms Engine Light ON (or Service Engine Soon Warning Light) P0237 Description The boost pressure sensor responds to pressure changes in the intake manifold. This pressure is created by the turbocharger and changes with accelerator pedal position (APP) and engine speed. The engine control module (ECM) uses this information to assist in diagnosis of the barometric pressure (BARO) sensor and to provide engine overboost protection. The boost pressure sensor has a 5-volt reference circuit, a low reference circuit, and a signal circuit. The engine control module (ECM) supplies 5 volts to the boost pressure sensor on the 5-volt reference 2 circuit, and provides a ground on a low reference circuit. The boost pressure sensor provides a signal to the ECM on a signal circuit relative to the pressure changes. The ECM monitors the boost pressure sensor signal for voltage outside of the normal range. The ECM calculates a predicted value for the boost pressure sensor. The ECM then compares the predicted value to the actual signal.
Read more: https://www.engine-codes.com/p0237.html

3

My first thoughts are using an additive to clean the induction system and combustion within the engine and an italian tune up to follow.

Reason being, low speed cutting out with a pressure charged system fault being flagged up can indicate a build up of carbon and the engine falls over itself.

It's too easy for the modern day engine to deliver chunks of power on demand but this is usually when at low revs and sometimes this can be the result. I would recommend the clean up first before committing big money to rectify further faults. By far the cheapest method to start with.

Also running on Supermarket fuel is definitely not a good option (not making assumptions that you fo this though)