Yaw sensor readings -ESP error

[Iang8560]

I have a DS3 2011 that I cannot clear the error c1136 steering angle coherence with no other errors on any ECU. I'm really stuck and spent hours this car and now exhausted with things to test.
I have tried many times to calibrate the angle sensor and yaw sensor and test says successful (but clearly isn't). I replaced the yaw sensor, steering rack, adjusted the wheel alignment and all live data (reported steering angle, torque applied, voltage, speed sensors, brake pressure etc perfect.

The only issue I can find is that the yaw sensor reports "invalid value" for yaw angle speed and transverse acceleration on 3 different diagnostic equipment. This has been successfully calibrated according to the scanner. I have tested the wiring to the sensor and get 13.5v (bat on charge), earth and 2v on pin 2 then 2.5v on pin 3. If I move the sensor no voltage changes occur. Can someone help please. What should the reading be from pin 2 or 3 when moving the yaw sensor? Is this the reason I cannot clear the c1136 issue or is this misleading me!!!

[GiveMeABreak]

You'll need to provide the VIN so I can relate this fault to the correct system. Please post your VIN in full without spaces - it will be automatically masked from public view after submitting your post & will only be visible to staff.

The operations vary according to the vehicle's equipment. For example, only vehicles with semi-automatic parking assistance have a steering wheel angle sensor (located in the steering wheel controls) - so won't be relevant if you don't have this option. The gyroscopic sensor for vehicles not equipped with this system are contained in the steering rack mechanism itself. I'll know more once you've provided your VIN.

[Iang8560]

Hello,

VIN is VF7**************[VIN obfuscated, can be read by forum staff]

[GiveMeABreak]

Ok, so you don't have semi-auto parking or parking assistance, so that eliminates that aspect.

So when we talk about the steering wheel angle sensor here, we are not talking about the sensor in the actual steering wheel as it's not present.

"a" Power steering electric motor.
"b" Steering wheel torque and angle sensor (Absolute steering wheel angle) (*).
"c" Electric power steering ECU.
"d" Steering rack.

(1) Pinion stem.
(2) Upper rotor.
(3) Lower rotor.
(4) Hall effect sensors support.
(5) Geneva wheel (*).
(6) Steering wheel angle sensor magnet.
(7) Gear.
(8) Torsion bar.

The Hall effect torque sensor has no contact.
The torque sensor located on the pinion shaft is used for measuring, in real time, the torque applied to the steering wheel by the driver (Value of the torque between + 10 Nm and -10 Nm).

The pinion stem (1) is linked to the pinion (7) via a torsion bar (8).

Each rotor consists of an opposition of South/North magnetic poles:

• The upper rotor (2) is solid with the pinion stem (1)
• The lower rotor (3) is solid with the pinion (7)

The torque applied on the pinion stem (1) by the driver creates a torsioning of the torsion bar (8), leading to an angular offsetting of the 2 rotors.
The angular offset of the 2 rotors produces a variation in the magnetic flow which is converted into an electric signal by 2 Hall effect sensors.
For vehicles that have ESP, the torque sensor is complemented by the following specific components:

• Geneva wheel (5)
• 2 Additional Hall effect sensors

The magnetic ring (6) measures the rotation of the lower rotor (3) via 2 specific Hall effect sensors : In this case, the steering wheel angle sensor continuously measures the value of the steering wheel angle during driving, relative to the steering wheel angle on starting the engine (Value of the angle varying from + 360° to - 360).
The Geneva wheel (5) gears onto the tracks of the lower rotor (3) in such a way that it turns 1/10th of a rotation for every 180° of rotation of the upper rotor (2).
The Geneva wheel (5) measures the steering wheel angle on starting.
Note: (*) According to version.


Pin Outs

Channel number	Allocation of channels of connector
1	Ignition+
2	IS CAN High
3	IS CAN Low

The steering wheel angle sensor must be calibrated in the following cases:

• Adjustment of the tracking
• Change of direction
• Work carried out on the steering column or mounting
• Appearance of the fault "steering wheel angle sensor fault": "calibration of the sensor incorrect", or "sensor never calibrated"

Ideally Diagbox is the preferred diagnostic tool, but here is what the code means:

Fault Code:	C1136
Description of Fault:	Steering wheel angle sensor fault. Coherence fault. The value of the offset of the steering wheel angle is greater than 15°.
Conditions for Fault to clear:	The following conditions have to be met: - After switching the ignition off and then back on - When driving above 11 km/h
Downgrade Modes whilst Fault is active:	Cutting of all ESP operations Switching on of the warning lamp and/or warning message: Warning lamp ESP
Symptoms:	Lighting of the ESP warning lamp with error message
Suspect Areas:	Interference Steering wheel angle sensor integral to the electric power steering

Also note: Tyres of a different model or with different wear on the same axle may alter the steering wheel angle information

[Iang8560]

Hey, GiveMeABreak -Thankyou for the quick reply and detailed information.

Can I assume the image is the steering rack itself or is this sensor shown as item 6 etc located elsewhere hopefully so as I've changed the rack already? I've got access to the parts page and can't see anything else within the parts pages that may apply.

The live data shows 0 degrees when the steering wheel is perfectly straight so I don't understand why the car thinks its wrong unless it has 2 reference points if that makes sense (both ref points aligned to confirm readings to satisfy the ESP/ABS module) Surely it needs two readings to know if something is wrong. I have tried calibrating it many times and displays it as calibrated then when rotating the wheel the - and + appear smooth and consistent, all data does. The fault wont clear whatsoever so its obviously not happy somehow/somewhere.

Could you also give advice on calibrating?. It says 100m but at what speed do I need to be at? less than 20mph etc, should the engine be left running once I've driven 100m, can I lightly steering the car due to road camber etc?.

I'm so happy to have someone technical to assist me!!. Thanks again

[GiveMeABreak]

The overall assembly is shown below of which the parts in my last diagram show a bit more detail of the components. (I'll also copy this back into the original post above to help viewing at the same time.

"a" Power steering electric motor.
"b" Steering wheel torque and angle sensor (Absolute steering wheel angle) (*).
"c" Electric power steering ECU.
"d" Steering rack.

[Myles97]

Any update on the conclusion for this? Thanks