MajorCommonTransmission

Citroen C5: SM6 Gearbox Hydraulic Actuator Failure

SM6 Gearbox Hydraulic Actuator Failure is a common transmission fault on the Citroen C5 on the 2008–2017 cars, and we rate it major. Putting it right costs $2,800 to $7,000 at New Zealand independent workshop rates. Below is what goes wrong, the symptoms to notice on a test drive, where to look, and what to ask the seller before you hand over any money. It is one of 15 documented faults on the Citroen C5.

Vehicle: Citroen C5
Engine: 2.0L
Years: 2008–2017
Fuel: petrol
Gearbox: auto
System: Transmission

This page covers the Citroen C5 as a model. Some faults only affect particular engines or build years — enter a plate below to narrow the list to one car.

All Citroen C5 faults15 documented faults on this model

What you are looking at

No photograph available

We do not hold a verified photograph of the Mechatronic / valve body yet. We would rather show none than show a picture of a different part.

What goes wrong

The Aisin-sourced SM6 six-speed automatic transmission fitted to Citroen C5 V6 and 2.0 petrol models uses a hydraulic control module with solenoid-operated actuators to select gears. The actuator assembly is susceptible to internal seal degradation and solenoid wear, causing hydraulic pressure loss within the valve body. The transmission progressively refuses to engage specific gears, particularly second and reverse, before ultimately refusing all gear engagement. The failure can be intermittent initially — the car may drive normally when cold but refuse gears once warm. PSA and Aisin acknowledged the issue but no comprehensive recall was issued in NZ/AU. The actuator is a dealer-only component and pricing reflects this.

What you would notice

Refusal to engage reverse gear, especially when warm
Hesitation, shuddering, or refusal to change into specific gears
Transmission fault light or automatic gearbox warning on dashboard
Car stuck in limp mode with limited gear selection
Transmission jerking during gear changes at low speed

How to check it

Where to look. Hydraulic control module (valve body) inside the SM6 automatic gearbox unit, underside of vehicle

Test drive the car after it has fully reached operating temperature. Specifically attempt reverse several times. Engage all forward gears through a full drive cycle including motorway speeds. Ask about any history of hesitation or gear refusal. Inspect transmission fluid condition — dark or burnt fluid accelerates actuator wear. If a workshop inspection is possible: Check for transmission fault codes with a PSA-compatible scan tool.

Parts involved: Mechatronic / valve body.

What it costs to put right

$2,800 to $7,000 at New Zealand independent workshop rates. That is for this job on its own, not for the car.

An estimate, in NZD, for the repair as normally carried out. What a specific car costs depends on which part has failed and what it damaged on the way — treat this as the floor for a negotiation, not a quote.

Ask the seller

“Has the automatic transmission ever refused to engage reverse or any forward gear?”
“Has the transmission warning light ever illuminated?”
“Has the transmission fluid been changed, and at what mileage?”
“Has the gearbox actuator or valve body ever been replaced or reconditioned?”

Now check the Citroen C5 you are actually looking at

Everything above is true of the model, and it is free. What it does not tell you is whether THIS car has been looked after: its odometer history and whether the reading has ever gone backwards, whether there is still money owing on it, whether it has been reported stolen, how many owners it has had and what it is really worth today. That comes from the official records for that plate. Enter the plate for the free details, or get the full history and a market valuation from $13.49.

Not sure what you would be paying for? See what a full KickTyres check includes.

Where this comes from

The failure described above is documented in published sources — owner forums, technical service bulletins, recall notices and workshop write-ups — held in our fault database. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them, and it is a starting point for an inspection rather than a manufacturer statement.

Citroen C5 buyer questions

Is sm6 gearbox hydraulic actuator failure serious on a Citroen C5?

We rate it major and common on the Citroen C5. The Aisin-sourced SM6 six-speed automatic transmission fitted to Citroen C5 V6 and 2.0 petrol models uses a hydraulic control module with solenoid-operated actuators to select gears. The actuator assembly is susceptible to internal seal degradation and solenoid wear, causing hydraulic pressure loss within the valve body. The transmission progressively refuses to engage specific gears, particularly second and reverse, before ultimately refusing all gear engagement. The failure can be intermittent initially — the car may drive normally when cold but refuse gears once warm. PSA and Aisin acknowledged the issue but no comprehensive recall was issued in NZ/AU. The actuator is a dealer-only component and pricing reflects this.

How much does it cost to fix on a Citroen C5?

$2,800 to $7,000 at New Zealand independent workshop rates. That figure is for this job on its own. A car showing the symptoms on this page is usually worth either walking away from or negotiating down by at least the repair figure.

Which Citroen C5 years are affected?

Our research records this fault on the 2008–2017 Citroen C5. Build dates move around, especially on imported cars, so treat the range as the years to look hardest at rather than a guarantee either way. The official records tell you the exact build and first registration date for the car in front of you.