SavMan
Authorised Forum Sponsor
I had no idea where to post this thread as it would have crossed several catergories.
Let me start by thanking the following people
Olly @ PCS
Jack @ PCS
Andy @ PCD
Alps
2 guys from Germany
1 guy from US
Its a long story so grab a brew and then read on
Had some new headers fitted a few weeks ago and the very next day one of my secondary O2 sensors popped out while driving down the motorway and could be heard banging about under the car! Not sure if it was the fitting or the thread in the new boss that could have been faulty, anyhow not looking to point fingers it happened and as I was on the hard shoulder and this is where I learnt my first lesson.
Lesson 1. Just because O2 sensors can be switched off in a remap you still need them and the ECU still monitors them. The signal they send still affects the way the car runs.
So carried on my journey minus one O2 sensor, only had 3 miles to go but within a mile my CEL had come on. Pulled off the motorway and plugged in the O2 sensor and wrapped it around the other O2 sensor wires to stop it banging about. Cleared the codes and carried on, got a new O2 sensor the next day.
Lesson 2. Never trust a part is working and not faulty.
Put my new O2 sensor in and all seemed fine but over the next few days the car seemed to develop a misfire that got worse each time the car was used.
Check on STAR no codes relating to misfire, looked at live data and could see 2 cylinders out of range but not creating a misfire code. Also the new O2 sensor was showing a flat line no voltage at all.
However started to get some strange error's over the next few days, here are just a few
ESP faulty steering sensor
ESP cannot communicate with ECU
TCU cannot communicate with ECU
Faulty Throttle Body
Sec Air pump actuator
Faulty air recirculation
Faulty electric water circulation pump
Pulled out the O2 sensor and swapped banks and sure enough the new sensor was now showing faulty on the opposite bank. Ordered a new but this time direct from Mercedes.
Now this is where it gets interesting, left the car at the airport and when I returned the car would not open. Battery was completely dead, called the AA when they tried to get it started car would not even idle, alarms on the dashboard and would stutter to a halt. The car was picked up and taking to my house and I started on it straight away.
Charged battery, put on STAR and read the codes. Pages of the damn thing several actuators and sensors showed they had stayed on and as such drained the battery.
Car still ran like a dog was misfiring but still no codes to show why the misfire and on each start up I would get different errors.
Jack and Olly at PCS as well as Andy at PCD were great the took several calls (dozens) and guided me through what to test.
Took of my larger injectors and put on the stock ones, still the same. Pulled out my spark plugs and fitted standard ones I had removed from the car - still the same. Swapped coil packs and leads until basically had identified that I needed 2 new coil packs, so they car was running smoother but not perfect and after driving would slowly get worse as the car adapted.
So still left with two main issues, strange codes from different control units in the car and rough running after adaptation.
Jack at PCS suggested I check for CAN configuration errors and sure enough there were many. It no longer believed I had ESP or even a gearbox among others so set about adding each one at a time. But after driving the car I would get a different CAN error as well as ECU communication errors.
New O2 sensor arrived so fitted it and could not believe my eyes still had a flat line regardless of the bank I fitted it to, this was driving me to despair!
Dozens more calls later and a simple enough question, is your battery OK!
Well voltage was low and had been completely flat but it seemed to hold voltage and started OK, put the battery on a load test and fail. So got a new battery from MB, started reprogramming the CAN network as well as ECU settings and I could not believe this time they were staying. A big thanks to Alps for going out of his way as well as two guys that helped from Germany and one from the US, all of which I have met (some in person some virtual) through Mercedes forums.
Lesson 3 - Never forgot to check the basic's, I am not exactly sure how the battery affected the CAN control unit/network as well as how the different control units communicate with the ECU but it seemed to do the trick.
So now just down to one problem, rough running so simple question again what are the chances of getting two successive faulty O2 sensors - surely to slim to even think about. Well seeing as the MB one cost me £214 I thought damn it I will take it back and change it. Put the new O2 sensor in and set adaptation to default initialisation and hey presto now I have four O2 sensors with perfect synchronisation. So remember “Lesson 2. Never trust a part is working and not faulty” and of course
“Lesson 1. Just because O2 sensors can be switched off in a remap you still need them and the ECU still monitors them. The signal they send still affects the way the car runs.”
Checked STAR live data for each cylinder and all within tolerance, in fact rarely did any of them even move from the ideal setting.
So right now after over 50 hours of spanner and diagnostics effort I have a car that drives and has no faults and no misfires, I am not sure if I am out of the woods yet but once again thank you to the following people for helping over the last week I would not have solved it without your patience and knowledge.
Olly @ PCS
Jack @ PCS
Andy @ PCD
Alps
2 guys from Germany
1 guy from US
Let me start by thanking the following people
Olly @ PCS
Jack @ PCS
Andy @ PCD
Alps
2 guys from Germany
1 guy from US
Its a long story so grab a brew and then read on
Had some new headers fitted a few weeks ago and the very next day one of my secondary O2 sensors popped out while driving down the motorway and could be heard banging about under the car! Not sure if it was the fitting or the thread in the new boss that could have been faulty, anyhow not looking to point fingers it happened and as I was on the hard shoulder and this is where I learnt my first lesson.
Lesson 1. Just because O2 sensors can be switched off in a remap you still need them and the ECU still monitors them. The signal they send still affects the way the car runs.
So carried on my journey minus one O2 sensor, only had 3 miles to go but within a mile my CEL had come on. Pulled off the motorway and plugged in the O2 sensor and wrapped it around the other O2 sensor wires to stop it banging about. Cleared the codes and carried on, got a new O2 sensor the next day.
Lesson 2. Never trust a part is working and not faulty.
Put my new O2 sensor in and all seemed fine but over the next few days the car seemed to develop a misfire that got worse each time the car was used.
Check on STAR no codes relating to misfire, looked at live data and could see 2 cylinders out of range but not creating a misfire code. Also the new O2 sensor was showing a flat line no voltage at all.
However started to get some strange error's over the next few days, here are just a few
ESP faulty steering sensor
ESP cannot communicate with ECU
TCU cannot communicate with ECU
Faulty Throttle Body
Sec Air pump actuator
Faulty air recirculation
Faulty electric water circulation pump
Pulled out the O2 sensor and swapped banks and sure enough the new sensor was now showing faulty on the opposite bank. Ordered a new but this time direct from Mercedes.
Now this is where it gets interesting, left the car at the airport and when I returned the car would not open. Battery was completely dead, called the AA when they tried to get it started car would not even idle, alarms on the dashboard and would stutter to a halt. The car was picked up and taking to my house and I started on it straight away.
Charged battery, put on STAR and read the codes. Pages of the damn thing several actuators and sensors showed they had stayed on and as such drained the battery.
Car still ran like a dog was misfiring but still no codes to show why the misfire and on each start up I would get different errors.
Jack and Olly at PCS as well as Andy at PCD were great the took several calls (dozens) and guided me through what to test.
Took of my larger injectors and put on the stock ones, still the same. Pulled out my spark plugs and fitted standard ones I had removed from the car - still the same. Swapped coil packs and leads until basically had identified that I needed 2 new coil packs, so they car was running smoother but not perfect and after driving would slowly get worse as the car adapted.
So still left with two main issues, strange codes from different control units in the car and rough running after adaptation.
Jack at PCS suggested I check for CAN configuration errors and sure enough there were many. It no longer believed I had ESP or even a gearbox among others so set about adding each one at a time. But after driving the car I would get a different CAN error as well as ECU communication errors.
New O2 sensor arrived so fitted it and could not believe my eyes still had a flat line regardless of the bank I fitted it to, this was driving me to despair!
Dozens more calls later and a simple enough question, is your battery OK!
Well voltage was low and had been completely flat but it seemed to hold voltage and started OK, put the battery on a load test and fail. So got a new battery from MB, started reprogramming the CAN network as well as ECU settings and I could not believe this time they were staying. A big thanks to Alps for going out of his way as well as two guys that helped from Germany and one from the US, all of which I have met (some in person some virtual) through Mercedes forums.
Lesson 3 - Never forgot to check the basic's, I am not exactly sure how the battery affected the CAN control unit/network as well as how the different control units communicate with the ECU but it seemed to do the trick.
So now just down to one problem, rough running so simple question again what are the chances of getting two successive faulty O2 sensors - surely to slim to even think about. Well seeing as the MB one cost me £214 I thought damn it I will take it back and change it. Put the new O2 sensor in and set adaptation to default initialisation and hey presto now I have four O2 sensors with perfect synchronisation. So remember “Lesson 2. Never trust a part is working and not faulty” and of course
“Lesson 1. Just because O2 sensors can be switched off in a remap you still need them and the ECU still monitors them. The signal they send still affects the way the car runs.”
Checked STAR live data for each cylinder and all within tolerance, in fact rarely did any of them even move from the ideal setting.
So right now after over 50 hours of spanner and diagnostics effort I have a car that drives and has no faults and no misfires, I am not sure if I am out of the woods yet but once again thank you to the following people for helping over the last week I would not have solved it without your patience and knowledge.
Olly @ PCS
Jack @ PCS
Andy @ PCD
Alps
2 guys from Germany
1 guy from US
Last edited:
