WO3 - P2024 EVAP Fuel Vapor Temp Sensor Circuit

[HITECH]

Yesterday I lost power in the higher gears. The revs are not restricted but their just aint any power thru the range/gears. This P2024 seems to be the code coming back most often. Before I take off the EGR and clean it which is usually the 1st things to do on those cars can anybody give me some input on the fuel vapor temp sensor circuit in case it is actually something to do with that. Stuck EGR's give this error in past experience working on other cars. Why ? Ive no idea but they do, on the mercs anyway. I would really appreciate some input on this before I pop the bonnet up.

Car was running fine. intermittent P2626 and P2079. Started car in morning after a hard frost and was no power BUT IT WAS NOT IN LIMP MODE. Just seriously down in power. Oil and water are fine. Also the DPF is fine regardless of codes as Ive manually re-generated it succesfully and also checked soot % etc. All fine there.
Im hazarding a guess at a major EGR and pipework clean out. What u think ?

Its a 170,000 miles C220 CDI 2004 (54 plate) with DPF, 2.1 963 engine.
Regularly serviced always (twice a year) and not just when a fault appears.

 

[HITECH]

I have a suspicion it is because of a faulty O2 sensor. Have a P0427 coming up after some work today and more test drives and scans.....

Yesterday I lost power in the higher gears. The revs are not restricted but their just aint any power thru the range/gears. This P2024 seems to be the code coming back most often. Before I take off the EGR and clean it which is usually the 1st things to do on those cars can anybody give me some input on the fuel vapor temp sensor circuit in case it is actually something to do with that. Stuck EGR's give this error in past experience working on other cars. Why ? Ive no idea but they do, on the mercs anyway. I would really appreciate some input on this before I pop the bonnet up.

Car was running fine. intermittent P2626 and P2079. Started car in morning after a hard frost and was no power BUT IT WAS NOT IN LIMP MODE. Just seriously down in power. Oil and water are fine. Also the DPF is fine regardless of codes as Ive manually re-generated it succesfully and also checked soot % etc. All fine there.
Im hazarding a guess at a major EGR and pipework clean out. What u think ?

Its a 170,000 miles C220 CDI 2004 (54 plate) with DPF, 2.1 963 engine.
Regularly serviced always (twice a year) and not just when a fault appears.

 

[HITECH]

Any input on this one guys while I'm waiting for the exhaust manifold pressure sensor to come in the post ?

 

[ashenfie]

PO427 if I have it right is say the No.2 cat sensor is not working correctly. Its a temp. sensor and either the wiring or sensor is defective. It's a effectively a resistor that reduces resistance as the cat warms up.

 

[HITECH]

Yeah that makes sense m8. I’ve just sorted out my power loss problem after fitting the sensor today. A faulty exhaust manifold back pressure sensor (just beside EGR valve) had packed in. I was doing some testing with it today tho. Once I established new sensor sorted the problem. I put the old one back in for test drives to see what codes the faulty sensor can throw (false positives pointing to other components). Ok it was throwing up errors below. This is in order of how they appeared to begin with and the power loss fault occuring as I have taken the info from a flight recorder mode with freeze frame data for each code.

5 Test drives with faulty sensor fitted went as follows:

1. Loss of power when I hit 60mph but doesnt restrict to 3000rpm. Maybe disables turbo but still gives rpm range.

2. PO2024 (most likely appeared after switching engine off/on during free wheeling - as mine is a manual) - False Positive
3. PO2079 (most likely appeared after switching engine off/on during free wheeling - as mine is a manual) - False Positive
4. P01408 (False Positive)

5. P0471 (The real fault - Positive Fault)

6. P0401 (False Positive)
7. P0403 (False Positive)

So my conclusion after ruling out the DPFE sensor is that the faulty exhaust back pressure sensor can throw those error codes above up on your diagnostics and that includes coming up on a STAR scan. The other codes came up before the actual proper fault code which is P0471. This will send you up the garden path with the troubleshooting because you concentrate on the present codes that come back the most. Although the P0471 states that it can be faulty wiring with the sensor. Its very highly doubtful. Definetely I would say on the C220 CDIs that the P0471 fault is nothing else other than changing the sensor to remedy the problem.

That is my conclusion to this fault. I can imagine with the fault codes this sensor can kick up that garages are prone to change EGR valves, DPF's MAF's and all sorts of components. I spent a lot of time with this today test driving, with faulty part in and live logging enabled just to cover the whole picture with it. Hope it helps others.