Engine warning light comes on during acceleration

Questions specifically about a Diesel powered C3 (usually engine or fuel related problems)
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Diesel engine related problems
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My Name: C3CAR

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Posts: 2661
Joined: Wed May 04, 2011 10:01 am
Model: C3 2002-2005, Original shape model
Year: 2002 (02)
Engine Size: 1.4 (16v)
Fuel Type: Diesel
Mileage: 140000
Trim Level: Exclusive
Gearbox: Manual 5 speed
DPF: No
LHD or RHD: RHD (UK)
Engine name: DV4 16-valve diesel (90 PS)
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MistyCottage wrote:Thanks for your help C3CAR. FYI the diagnostic tool is a Snapon Versus unit that has auto identified the engine as a 8HY version, and identified the ECU as a Delphi C6 Part No:9653977080. I've attached the printouts for the initial up hill run.
Thanks for the info.

Image
The flat line on the atmospheric sensor looks like default values are replacing the proper reading from the sensor itself.

It is unusual for the atmospheric sensor to be faulty and its not great news as the sensor is integrated into the Engine ECU :(


MistyCottage wrote:Before I replaced the MAP/pressure sensor, I was getting a similar turbo pressure (measured) graph but from time to time it would lock at a pressure reading giving a flat line, for a number of seconds. If that time exceeded about 5 seconds, then the engine light would come on, and economy mode started, until the car was restarted.


The flat line would probably be some default value because the sensor was faulty, although only intermittently.

You suggested I disconnect the Mass Airflow Sensor, other than a change in the measured airflow and air intake temperature, am I looking for anything else? Thanks.
Thanks for doing those extra tests, I wanted to be sure that the scan tool was reporting the reading correctly because it such a rare problem.

I would be looking at the engine ECU and in particular the atmospheric sensor, but its difficult to get to :cry:
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My Name: C3CAR

Guru
Posts: 2661
Joined: Wed May 04, 2011 10:01 am
Model: C3 2002-2005, Original shape model
Year: 2002 (02)
Engine Size: 1.4 (16v)
Fuel Type: Diesel
Mileage: 140000
Trim Level: Exclusive
Gearbox: Manual 5 speed
DPF: No
LHD or RHD: RHD (UK)
Engine name: DV4 16-valve diesel (90 PS)
Has thanked: 176 times
Been thanked: 93 times

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atmospheric pressure sensor for a citroen C3
atmospheric pressure sensor for a citroen C3
The pressure sensor (1) is integrated into the injection computer.
Caution: The sensor is not separable from the ECU.
My Name: MistyCottage

Contributor
Posts: 11
Joined: Fri May 09, 2014 12:19 pm
Model: C3 2002-2005, Original shape model
Year: 2003 (03)
Engine Size: 1.4 (16v)
Fuel Type: Diesel
Mileage: 108000
Trim Level: Exclusive
Gearbox: Manual 5 speed
DPF: No
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I've been advised that the Delphi 9650043480 80929Q are notoriously difficult to get into to repair. I now have access to a Lexia tool, and have purchased a kit consisting of Key Fob, BSI unit and Delphi ECU (same part numbers as original) from a breakers. Can anyone offer any advise as to whether I just swap the lot into the car, and redo the tests ? I've heard that this should work but my car mileage will change to the donor vehicle and the radio will stop working. So the question are:

1. is this totally reversible if I need to reinstall the original BSI and ECU? i.e. will the mileage go back to original and the radio work again?

2. Can I use the Lexia to reprogram the radio? or

3. Can I reprogram the replacement ECU, leaving the original BSI in place, to work in the car using the Lexia or will I need something else?

Any helpful comments are highly appreciated.
My Name: MistyCottage

Contributor
Posts: 11
Joined: Fri May 09, 2014 12:19 pm
Model: C3 2002-2005, Original shape model
Year: 2003 (03)
Engine Size: 1.4 (16v)
Fuel Type: Diesel
Mileage: 108000
Trim Level: Exclusive
Gearbox: Manual 5 speed
DPF: No
Been thanked: 3 times

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Thanks again to everyone's help on this. I eventually found the fault. It would appear that the last owners so called 'mechanic' had reversed the two vacuum pipes on the turbo waste gate solenoid. This meant that that the turbo boost was constantly on, causing an overpressure situation, and also the vacuum reservoir kept being opened to the atmosphere! Easy fix, but boy, what a lot of wasted time and expense in swapping ECU setups and the mileage correction that needs to be done after swapping back.
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My Name: Arfur Dent

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Posts: 3423
Joined: Sat Jul 23, 2011 3:47 pm
Model: C3 2002-2005, Original shape model
Year: 2002 (52)
Engine Size: 1.4 (16v)
Fuel Type: Diesel
Mileage: 100000
Trim Level: Exclusive
Gearbox: Manual 5 speed
DPF: No
LHD or RHD: RHD (UK)
Engine name: DV4 16-valve diesel (90 PS)
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MistyCottage wrote: I eventually found the fault. It would appear that the last owners so called 'mechanic' had reversed the two vacuum pipes on the turbo waste gate solenoid.
Thank you for posting the solution! Difficult to find as you wouldn't reasonably expect this to happen through a degradation of parts or a breakage.
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