ESP ASR/BAS & APPS FAULTS

Good day everyone 

I need help on a Mercedes sprinter 2007 CDI OM 646 engine 
ABS and brake lights go off when engine is started, but ESP ASR/BAS lights stay on

the following DTC’s are current and stored under ESP7201 The CAN message from control module Engine is invalid or implausible 
51A5 CAN signal acceleratior pedal value invalid
7266 cruise control - control unit N30/4 (ESP control unit) not available The following DTC is stored under engine DRIVE
51A5 CAN signal acceleratior pedal value invalid

I have 5v on Apps sensor 1 and 2
i have sensor 1 ground 0.14v
I have sensor 2 ground 0.01v
i have good signal voltage on apps sensor 2, and also the xentry software reads 0%at idle and 100% at WOT
I DO NOT have any voltage or percentage readings on apps sensor 1 signal 
How do I address these faults 
where should I start from 

Is the apps fault causing the esp bas/asr faults 
is the esp BAS/asr causing the apps fault 

kindly give your expert advice sirs 

Guys kindly help take a look at this for me

Do you have access to service information for this vehicle?
Shop Key has no option for a 2007 Mercedes Sprinter, so I am assuming this is not a US market vehicle. I have no idea what a ”CDI OM 646 engine” is or what module "ESP7201" is responsible for and there for, obviously, no helpful input.
Based on the description of the tests you performed and the lack of voltage on one APP signal circuit, it sound likely the accelerator pedal is failed. But without service info to determine why that code sets, what modules are involved or how the circuit is built, I'm out in the weeds.
Hopefully someone who has experience with this vehicle in their country can offer some insight.
If you are not all ready a member, you may have more success on a platform geared specifically to professional auto techs such as IATN or Diag.net

The vehicle is European

OM 646 is the engine type
7201 is the DTC

ESP is electronic stability program
I don’t have access to service information
I know it’s not the pedal because I’ve swapped over 7 pedals with same part number

I’ve watched scannerdanner YouTube videos on circuit integrity on 5v ref and signal

When I unplug the pedal, the working signal voltage jumps to zero. So it’s hard to test this circuit for 5v on the signal wire with the unplugging test.

DTC 7201 is so vague and not pointing specifically to anything
Anyone with any idea on how to tackle this DTC

Another funny way I was able to tell that the signal wire circuit is fine is this

Under sensor 1 of the pedal, I have 5v ref, 0v signal, 0.14v ground
Since the ground voltage is so high, I cut the ground wire off from the ECU and wired it to a chassis ground and all sort of results came up

Sensor 2 ground became the 0.14v and its signal wire works and revs

Sensor 1 ground drops to 0.01v and the signal wire has 0.14v and yet won’t rev

This makes me believe the programmers have asked the ECU to disable sensor 1 signal of the pedal whenever ESP and traction control has a fault.

I also believe this is what’s happening when in some vehicles pedal DTC comes up when the brake light switch is bad and the back brake light stays ON

I watched a video also that says some engine performance DTC can trigger ESP light

So I’m really confused

Let’s say any of you experts are confronted with this scenario

Where do you start your fix from
Engine DTC or chassis ESP DTC?

Let’s say any of you experts are confronted with this scenario Where do you start your fix fromEngine DTC or chassis ESP DTC?

I would need to start with referencing service information. Step one is becoming familiar with the system. Without understanding the code set criteria, failure mode strategy or how the circuit is built, there is zero possibility that I could diagnose this if it was in my shop.
My advice is get your hands on a field service manual or internet based service information.
I do hope you are able to find the correct information and can resolve this issue even if I can't be of much help.

I am aware that OM646 is the engine type, but it is still Greek to me. That could be an inline diesel, 50cc 2 stroke chainsaw engine or Volvo boat motor for all I know.

Just a quick question forumites 

Can an illuminated ESP/traction warning lights on the dashboard cause an accelerator pedal DTC? 

I would imagine the inverse would be true: that the accelerator pedal position code being set would cause illuminated ESP/Traction warning lamps.

Thanks so much Noah

Time to chase down my APPS signal low voltage fault 

but again I’ve seen several cases of APPS DTC being set by back brake light bulb staying on when engine is off and key is out 

in my own case I’m having a hard brake pedal like a brake master servo not working 

The DTC I’m getting under esp doesn’t explain exactly where the implausible signal is happening 
DTC 7201 The CAN message from control module Engine is invalid or implausible

Are they referring to the ABS module as the “control module engine”?
i don’t have any back brake light staying ON Key out engine off 

DTC 7201 The CAN message from control module Engine is invalid or implausible

It means that the ecm has an invalid information in there, some sensors that work with the ecm is giving fault message, so if you solve the app problem that is link to the ecm, the abs will be fine too

Thanks guys

i have tried to make sense of this DTC 7201, but it’s very confusing 

The DTC 7201 is not listed under drive aka ECU after scanning the vehicle, rather it’s listed under ESP. This makes me believe the control module engine being referred to here is the ABS 
I have changed my ABS module and still same problem. 
I will use some scannerdanner materials on signal voltage fault to troubleshoot my APPS

When I changed my shock absorber front driver side, the ESP light would go off and on, unfortunately I was unable to read the vehicle DTC at that time to see if my APPS DTC had gone. But when I took out the shock absorber again to replace the shock absorber stabilizer bushing and swap the out the shock absorber itself a second time, the ESP light now stays ON permanently. The reason I swapped out the shock absorber a second time is because the previously replaced shock damaged my tyre within 2 weeks, causing the tyre to become uneven in the middle thread area. The esp light was going off and on during this time. I’m suspecting the esp/traction fault is caused by some problem in the tyre area of the front driver side. I swapped out complete bow joint and it’s arm, stabilizer linkage, shock absorber and it’s stabilizer bushing and then did an alignment with the hope this would solve my problem, but unfortunately the esp light stays ON permanently. 
So without fixing my Apps DTC my ESP light was going on and off, which threw me off to believe that the ESP illuminated light is not tied to the APPS fault 

(((Other common reasons for the ESP light to come on include traction loss, faulty sensors, brake system issues, faulty ABS system, incorrect wheel alignment, low tyre pressure, faulty wiring or connectors, damaged battery, steering angle sensor, turbo hose tear, corrupted software, and bald tyres.)))))

No body asked you for change abs module, you did that out of your own curiosity..

I am saying solve the app error on the ecm side and you will be fine to have a happy abs

APPS  SENSOR right to left wire reading 
1. Yellow/red. 5v  supply sensor 1
2. Yellow.   Signal 1 signal voltage is too low (short to ground or open signal wire) 0.03v
3. Yellow/brown. Sensor 1 ground 0.14v 12.52v to battery positive 
4. Brown/white.  Ground 2 0.01v sens 2 12.66v to battery positive 
5. Pink/violet 5v supply sensor 2 shares with boost pressure sensor on the intake beside MAF via connector Z7/86
6. White signal 2 works fine 0.14v at idle

I did the unplugging test and still got 0.03v on the affected sensor 1 signal wire 

I thought it was a ground problem and gave it another ground directly to battery ground 

Sensor 2 that is working 
Ground 0.01v
Signal 0.14v

Sensor 1 that’s faulty 
Ground 0.14v
Signal 0.03v
It’s the ground that should be 0.03v and signal 0.14v I believe

i have looped another wire from the ECM to the apps faulty signal wire just to eliminate a short or open in the wire, and it’s same problem 

What do you guys think is going on here 
sensor problem?
wiring problem? 
ECM problem? 

Update on the fix for my apps dtc
After series of tests, I realized that the ground for the faulty apps sensor 1 was not the best. I connected a different ground wire from the battery negative terminal to the apps sensor 1 ground and that didn’t fix it, I also used the ground wires coming from the air flow meter and 
MAP, but that didn’t fix it either.

I have now combined the ground wire of apps sensor 2 to sensor 1 ground and my apps DTC went away. Although I’m having a feeling the problem might also be coming from the connector of apps. But for now I’m so happy I’m putting the apps fault behind 

My vehicle is still in limp mode though, with exhaust gas recirculation DTC.

I’m going to find my way around or open a new thread for that if it’s too difficult for ne

Special thanks to everyone that responded here 

The fix of this apps DTC this time around is fixing the ground

a rule of thumb I followed was knowing that a good ground should read 0.01v, anything higher than that is very suspicious