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Discussion Starter · #1 ·
A180 CDI BlueEFFICIENCY Sport 5d 2014

After a bit of googling and responding to several threads on forums and on FB, I have found that my problem is quite common but as yet to find someone who has fixed it.

Problem: Engine management light comes on, along with both the ESP warning light and ESP OFF light - the car goes into limp mode.
Switch the car off and on again and both ESP lights go out but the engine management light remains.
Car drives normally again. left overnight or for a while and the engine management light goes off too.

I have had it plugged into a diagnostic machine and all sensors came back as fine.

It was all good for a few days but now it has reappeared.

somethings I have noticed: it only seems to come on when the car is hot/warm or after a long journey or hot day.
for eg: drove to Weymouth the other day ( approx 40 miles, just over an hour away) and what absolutely fine on the way there. After the car had sat in the sun all day, 10 mins into the journey it came on again.

Going to work in the mornings is fine, coming home, again now the weather is hot, it comes on again.

Hopefully, someone can help :)


8181
 

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You need to plug it into a code reader that will read the stored code on the Engine ECU.

A EML will have stored a fault code.

Not all 'generic' code readers or diagnostics can read or reset manufacturer specific ECU codes, it has to be one that lists your car make/model.
 

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I bought an Icarsoft MB V2.0 for my wife as she has an A Class 2013 and she has been having intermittent faults with the ESP and Engine Management lights that then put the car into Limp mode, I work away most weeks so didnt want her to be stranded for what appears to be faults that dont seem to exist, a quick reset and she seems to be ok, sometimes for a prolonged period but this week she has had the fault constantly, I have today disconnected the ECU in the engine checked all the contacts and the wiring to make sure no obvious signs of damage, reset the errors checked the battery voltage with no load which sits at 12.4V and around 14.2V with the engine idle, this I think would eliminate the battery theory, all wheel sensors are reading ok, the steering wheel position sensor is ok, the lateral sensor also reads ok, I have checked this via the Live Data from my diagnostics tool, tomorrow I am sure will give me another headache with another set of different faults from my diagnostic tool. I will continue to feedback until I find the solution or persuade my wife to get rid of her Merc and buy something less complex.
 

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Discussion Starter · #4 ·
I have had it plugged into a code reader first and came up with P0229

.


P0229 code definition
Throttle/Pedal Position Sensor/Switch C Circuit Intermittent
What the P0229 code means
P0229 is an OBD-II generic code indicating the throttle/pedal position sensor/switch C circuit has an intermittent input problem causing the sensor input to the engine control module (ECM) to be intermittent and within the the expected voltage input when compared to the throttle position sensor A.
What causes the P0229 code?
  • The engine control module (ECM) detects erratic input voltage from the sensor circuit to the ECM, but still within the specified range for the sensor when it is working.
  • Corrosion in the connections to the sensor can cause the erratic voltages from the sensor.
  • Loose connections to the sensor can cause the voltage to be erratic.
 

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Discussion Starter · #5 ·
Same year, same fault. Wonder if Mercedes are aware of this. Or perhaps they like us to keep returning and paying the bucks to have our cars examined ?
 

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Components do wear out and fail, and if it's a throttle pedal sensor(s), you'll just have to stump up for a new one, same with any other manufacturer?
 

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Discussion Starter · #7 ·
That's my next port of call.
But I have found numerous threads on various message boards, from people that all have the same problem and even Mercedes cannot pinpoint what the fault is.
one person has stumped up hundreds of pounds to Mercedes and everytime she leaves the garage its fine then a few days the same fault comes back.
 

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Discussion Starter · #8 ·
Just been told that they cannot source an Throttle pedal sensor for an A class Merc and to perhaps look on eBay. Seems to me no such thing exists !! #reallymissingmyhonda
 

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So update on todays work; -
I have checked all the ground connections in the footwell and the engine bay all look to be ok,
I have removed the plugs from the ECU and checked all the connections which look to be ok re-seated the plugs and check any wiring that was easily accessible, didnt see anything that could cause an issue though.
The battery terminals have been tightened by about 3/4 of a full turn wouldnt say they could cause an issue but not an issue to make sure they are tight enough.
Originally I had an issue with my door lock switches they had been disconnected before my wife bought the car, I reconnected this but noticed some damaged cabling to the driver door ECU, I have now repaired the damage did a diagnostics check and had a fault with a malfunctioning mirror heater on the driver side and some CAN bus errors??? Removed the mirror and found a damaged female crimp terminal on the heater, heater resistance tested at around 22 mohm so all good I have replicated this fault which intermittently brings up either a mirror heater fault, CAN Bus error only the pedal switch unreadable or data at the CAN module cannot be read (or something very similar been a long day).
I have replaced the brake pedal switch sensor but this caused a fault with the ESP although didnt bring on limp mode, put the old sensor back on and reset the brake sensor fault from the diagnostics list and all cleared,
Been out for a drive a couple of times but will see what the next few days brings.
In theory if the car is shorting the ECU and causing an error to ground this could cause a ECU/CAN error, a bad reading from the mirror heater cables touchng without the resistance of the heater could create parallel paths and erratic readings, I dont know the whole wiring layout for Merc but in the industrial world parallel paths can create issue with various systems so just a case of seeing how the next few days go but I definitely check the doors and the mirror heater connections, most of the faults I have seen on my diagnostic reader have not helped and have been errartic, will feedback in the next few days how its going but not holding my breath, issues have been sorted so will see what else crops up next.
 

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A180 CDI BlueEFFICIENCY Sport 5d 2014

After a bit of googling and responding to several threads on forums and on FB, I have found that my problem is quite common but as yet to find someone who has fixed it.

Problem: Engine management light comes on, along with both the ESP warning light and ESP OFF light - the car goes into limp mode.
Switch the car off and on again and both ESP lights go out but the engine management light remains.
Car drives normally again. left overnight or for a while and the engine management light goes off too.

I have had it plugged into a diagnostic machine and all sensors came back as fine.

It was all good for a few days but now it has reappeared.

somethings I have noticed: it only seems to come on when the car is hot/warm or after a long journey or hot day.
for eg: drove to Weymouth the other day ( approx 40 miles, just over an hour away) and what absolutely fine on the way there. After the car had sat in the sun all day, 10 mins into the journey it came on again.

Going to work in the mornings is fine, coming home, again now the weather is hot, it comes on again.

Hopefully, someone can help :)


View attachment 8181
hi im newbie try to answer,

the problem its seem similar with mine before but different error code. ESP error & engine check light on intermitten then the car goes to limp mode.

i try to conneted icarsoft i980 to OBD port, then it says: sensor error on front left ABS speed sensors. I tried to disassemble the left front wheel and found the speed sensor cable seemed to rub against another piece of metal. I tried to strengthen it with a spiral cable as picture, until now its works fine for me. Research from several mb forums, mostly ESP errors are caused by this sensor. hope its helps.

8298
 
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