Fault code p2128 C4 GP 1.6 diesel 2012

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bbfn2001
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Joined: 28 Mar 2023, 07:34

Fault code p2128 C4 GP 1.6 diesel 2012

Post by bbfn2001 »

Was wondering if someone could help, a few days ago my rocker cover gasket was replaced, I drove the car a short distance and parked it up until this morning and when I drove it the engine management light came on with warning about engine fault/ repair. When I scanned for code I got p2128 Throttle/Pedal Position Sensor/Switch "E" Circuit High Input. Could this be just a coincidence to the work done to the rocker cover or is it to do with the throttle pedal and sensor only? I looked at the pedal sensor and there seems to be a date on it which looks like 09/2023. Any help would be appreciated

Thanks
Last edited by GiveMeABreak on 23 Apr 2023, 12:19, edited 2 times in total.
Reason: Corrected Post Vehicle Year to 2012 and removed member info - as not needed
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GiveMeABreak
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Re: Fault code p2128 C4 GP 1.6 diesel 2012

Post by GiveMeABreak »

Here's the code description:
Fault Code: P2128
Description of Fault: Measurement of the air mixer position: Short circuit to positive or open circuit. Electrical fault. Voltage higher than 4,9 V for 500 ms.
Conditions for Fault to clear:
  • Driving for 5 minutes
Downgrade Modes whilst Fault is active:
  • Inhibiting of the injectors reset strategy
  • Closing of the EGR (exhaust gas recycling) valve
  • Reversible deactivation of the vehicle speed limiter
  • Reversible deactivation of the vehicle cruise control
  • Inhibiting of the air flow sensor reset strategy
  • Deactivation of the request for regeneration of the particle filter from the diagnostic tool
Symptoms:
  • Engine stop downgraded
  • No automatic stopping of the internal combustion engine
  • Noise
Suspect Areas:
  • Air metering valve
  • Electrical harness
  • Connectors
Please Don't PM Me For Technical Help

Marc
bbfn2001
Posts: 20
Joined: 28 Mar 2023, 07:34

Re: Fault code p2128 C4 GP 1.6 diesel 2012

Post by bbfn2001 »

Ok now a further development, I took car out for a run and at when you Accelerate hard the esp light comes on and a warning on dash esp/asr system faulty. Reading codes I’m getting p2128 and now p11ab. I can clear the p11ab and the esp light goes off until hard acceleration then it comes on again with the same warning.Also the car goes into limp mode. Any help appreciated
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GiveMeABreak
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Re: Fault code p2128 C4 GP 1.6 diesel 2012

Post by GiveMeABreak »

Because this fault results in the 'torque uncertain' message being sent on the CAN network as part of the 'Downgraded Modes' this will affect the the data the ESP ECU receives and in this case it would appear it won't know the engine speed. So this is a knock-on effect fault and you need to focus on resolving the P11AB first.

A common cause can be the vacuum circuit or the solenoid. Some solenoids have a filter that can become clogged up. So a few things to check.
Fault Code: P11AB
Description of Fault: Air circuit: Turbocharging pressure below the maximum threshold.

Possibility 1: Incoherence between the measured position of the turbocharger electrovalve and the measured turbo air pressure, as detected by the turbo pressure being lower than 0,9 bars for 3 seconds at idle.

Possibility 2: Incoherence between the measured position of the turbocharger electrovalve and the measured turbo air pressure, as detected by the turbo pressure being lower than 1,3 bars for 3 seconds under load.

These thresholds are weighted according to the atmospheric pressure.
Conditions for Fault to clear:
  • Driving for 5 minutes with several full load accelerations
Downgrade Modes whilst Fault is active:
  • Closing of the EGR (exhaust gas recycling) valve
  • Irreversible deactivation of the vehicle speed limiter
  • Irreversible deactivation of the vehicle cruise control
  • Deactivation of taking account of the tight spot information
  • Switching of the turbocharging pressure regulation to controlled mode
  • Switching to fuel "normal reduced flow" mode
  • Deactivation of the request for regeneration of the particle filter from the diagnostic tool
  • Sending of the information "torque uncertain" on the CAN network
Symptoms:
  • Lack of power
  • Smoke from the exhaust
  • Noise
Suspect Areas:
  • Manifold air entry pressure sensor
    turbocharger
  • Turbocharger variable geometry control solenoid valve
  • Turbocharger variable geometry position repeat sensor
  • Electrical harnesses
  • Connectors
  • Vacuum circuit leak
Please Don't PM Me For Technical Help

Marc
bbfn2001
Posts: 20
Joined: 28 Mar 2023, 07:34

Re: Fault code p2128 C4 GP 1.6 diesel 2012

Post by bbfn2001 »

Also I forgot to mention that the car is only blowing out cold air and was before the rocker cover gasket replacement , could this have anything to do with the codes that only came up after the garage work. Also would a new throttle/ position sensor remove the code 2128. Thanks again.