Peugeot 508 2012 - ESP issue

[Overlodei]

Hey everyone,

I have a Peugeot 508 2.2 HDi automatic, and I’m trying to understand an ESP / steering angle sensor issue that started after replacing the steering rack.

Here’s the full situation.

A while ago I replaced:

steering rack
tie rod ends
timing belt
coolant
battery (brand new Bosch battery)
AC system repair
wheel alignment

After the steering rack replacement, I started getting ESP / ABS related errors.

The mechanic already tried:

steering angle sensor calibration
clearing all faults
wheel alignment

Calibration did NOT fix the issue.

The strange thing is:

the steering angle sensor DOES react in live data
when turning the wheel, the values change correctly into positive/negative degrees
so the sensor is not completely dead

One mechanic thinks the steering angle sensor board/module itself is faulty and wants to replace it.

Another possibility I’m considering:

steering rack may not have been centered mechanically during installation
or steering wheel / rack geometry is now out of sync
causing ESP coherence errors

Current symptoms:

ESP / ABS warnings
steering angle related faults
gearbox also receives invalid ESP data
sometimes random electrical faults appear/disappear

Important fault codes:

ABS / ESP:

C1136 — Steering wheel angle sensor signal coherence fault
U1205 — No communication / invalid data from steering angle sensor

Automatic transmission:

U1213 — Invalid data received from ESP system

Engine ECU:

P0091 — Fuel pressure regulator fault
P0003 — Fuel flow regulator control fault
P0685 — Main relay / power relay fault
P1443 — Additive pump connected by wire fault
P2426 — EGR cooler bypass valve fault
P16A7 — Crankcase gas recovery system heater A1 fault
P16A6 — Crankcase gas recovery system heater A1 fault
P0611 — Injector reset fault
P0215 — Principal relay control fault
P250D — Oil level sensor fault

BSI:

U1F00 — Fault event not logged
U1F05 — Multiplex network wake-up line fault
B1167 — Front left turn signal fault
B1818 — Oil level fault

Some of these may be old/intermittent faults caused by previous battery problems, because many of them are marked as intermittent.

What confuses me:

steering angle values DO move correctly in diagnostics
calibration was already attempted
but ESP still says steering angle data is invalid

Questions:

Could this still be a bad steering angle sensor/module even if live data reacts normally?
How likely is it that the steering rack was installed off-center mechanically?
Could the issue come from the clockspring / COM module / wiring instead?
Is there a way to verify rack centering manually?
Can this realistically be fixed DIY, or is dealer-level Peugeot diagnostics required?

Would really appreciate advice from anyone experienced with Peugeot/Citroen ESP systems or steering rack replacement issues.

Thanks!

[myglaren]

Please don't post multiple identical questions, it just causes confusion.
For anyone with answers, post in this thread:-
viewtopic.php?p=868384#p868384