C5 X7 ES9A 3.0 V6 - P1335 low power

[Zosski]

Hello everyone,

Since January this year I'm owner of C5 X7 with 3.0 liters gas engine.
When I bought the car it had decent power - comparing to today situation.

Feburary 2026 - timing belt was done -
my friend said that on intake cams you cannot set it exactly as it should be since those engines do not have adjustable cam gear comparing to ES9J4S (I attached pictures how they were set comparing to marks)
DAYCO was used: https://motostacja.com/p/155053.html
April 2026 - rear camshaft cover was sealed

Somewhere around June just of curiosity I wanted to check what's the power of the car so I did dyno run - it came out about 180 HP and 220NM!

We've connected the diagnostic tool and only two errors were there:
P0021 - Position of crankshaft sensor rear cylinders - discontinuous error - it disappeared after cleaning errors
P1335 - Position of crankshaft sensor unknown, front and rear cylinders - permanent error - it keep coming back.

Those errors were never observed before - since I last check while changing the automatic gearbox oil end of May.

What have been done together with my friend:
-We check the signals from sensors (crankshaft + camshafts sensors) to ECU - they seem to be fine.
-We check the signals from sensors using oscilloscope however we lack knowledge if it can be an issue - it seems like rear camshaft is late (Camshaft angle offset) ~2 degrees comparing to front camshaft sensor data.
I attached images - seems that in exported images we have issue with high voltage but it was there in actual software (just missing in pngs).
CH1 is either crankshaft or camshaft front (Depends on image)
CH2 is always camshaft rear

Whenever P1335 is deleted it comes back after few seconds or minutes of idle or riding
VVT solenoids stop working at some point + crankshaft/camshaft synchronization says NO in the program, camshaft stays fluctuating around 35-37* and the P1335 is back.

Next thing we want to do is to at some point check solenoids of VVT and do oil pressure test.

It would be great if you have any advice or can give us opinion on data we collected using oscilloscope.

[mickthemaverick]

What year is your car?

[Zosski]

It's 2009 and about 118k miles right now.

Other than not working VVT while P1335 is there I don't have any other issues with it.

[Zosski]

Since my last post the problem hasn't gone away — it's actually worse.
After clearing P1335, the VVT now doesn't work at all, right from startup. Before, it would work for at least the first 2–3 km of driving.

The only thing I've changed since last time is ultrasonic cleaning of the VVT solenoids.

New measurements
-We scoped it again. The waveforms haven't changed much, but this time I got much better quality captures — attached.

I've also gottwo documents that may help:
-The PSA diagnostic sheet for P1335
-A drawing of the reluctor ring, showing the sensor axis position with the engine pinned. Posting it in case it's useful to others.
If you need it PM me.

-And a link to what looks like a correct waveform for this engine, though I can't confirm it: https://rotkee.com/en/waveform-library?engine=2244

Plan for the next 2–3 weeks:
1. Pull the covers and check the intake cam target wheel positions against the drawing + seal some oil leak in nearby areas.
2. Check the dowel pins between the VVT sprockets and the camshafts, plus the sprockets themselves.
3. Verify the belt timing was done correctly.

If all of that checks out, we'll try advancing the camshafts one tooth on the belt — our readings and the marks from my first post suggest they're currently retarded.

[Zosski]

Quick update:

One guy that I was tracing on facebook group have solved the issue with P1335 by moving reluctor ring and welding it in place - which seems to be common solution. He claimed to have some oscilograph waveforms, I've reached out to him to receive them.
I will post them here if he is willing to share.

[Stickyfinger]

I am confused with your post....C5x7 v.6 engine is not VVT yet you say you are getting readings from the VVT solenoids ?

There was no VVT on the engines fitted to the C5x7.....or am I wrong for your country cars ?

[Zosski]

Hi Stickyfinger,

It's 3.0 v6 gasoline not diesel. It has VVT and seems to be common problem.

[Kees]

In here vvt stand for Variable Valve Timing.
This is done by an solenoid.

[Zosski]

So today my friend created device with LED diodes that plugs into sensors to check the difference between signals of camshaft sensors. We assumed front ring was OK so we aligned rear to match front using screwdriver.
Based on device the rings on camshaft should be now aligned. In next day after dealing with some oil leaks I will update the topic if the issue was resolved and p1335 is gone or not.

[Kees]

I hope, that this will not end up in tears, because this part will easily break!!

[Zosski]

It’s been a few days since the adjustment. We didn’t get it spot on, but it’s now within the range where P1335 no longer shows up.
I’ve already done about 500 km, and at low RPM it honestly feels like a 3.0 L instead of a 1.6.

I can confirm that this part breaks easily. If anyone wants to try this “improper” method, I’d recommend at least adjusting it using the larger teeth, not the small ones.
The proper method would be to remove the camshafts, make the adjustment, and possibly lock the part in place with a weld.

I suspect the ring moves because of a faulty VVT pulley that rattles on startup. I believe that rattle is what shifts the ring.
Either way, I’d advise doing a proper repair on this part, and if you have VVT rattle, replace the pulleys.

If anyone needs them, I can share the oscilloscope readings from after the adjustment.