Fourth gear slipping.
P0734 — also written PO734, P 0734, 0734 — is the OBD-II code for gear 4 incorrect ratio. Same code, same fix: this page covers every spelling of it.
Gear 4 incorrect ratio — the transmission control module is measuring input and output shaft speed and the ratio in 4th gear isn't matching what it should be. Almost always a slipping clutch pack, a stuck solenoid, low or degraded ATF, or on later cars a failed mechatronic unit. On UK autos this hits VAG DSG/S-tronic, ZF 6HP/8HP boxes, and Renault/Nissan CVTs hard.
P0734 is a transmission fault code, typically costing £250–£2500 to put right in a UK garage.
What P0734 actually feels like to drive
- Judder / flare in 4th only, other gears feel fine
- Transmission drops into limp (usually 3rd) on motorway cruise
- Higher-than-expected engine RPM at 60–70 mph in 4th
- 'Gearbox fault — service required' on the dash
- Occasional clunk on downshift into 4th
What causes P0734?
- Worn clutch
- Solenoid
UK vehicles that throw P0734 most often
- VW Golf / Passat / Audi A3 / A4 / A6 DSG (DQ200 7-speed dry & DQ250 6-speed wet)
- BMW 3 / 5 / X3 / X5 ZF 6HP / 8HP (E90, E60, F30, F10, E70)
- Land Rover Discovery / Range Rover ZF 6HP26
- Ford Focus / Fiesta / Kuga PowerShift dry-clutch (DPS6)
- Nissan Qashqai / X-Trail / Juke CVT (Jatco JF011E/JF017E)
- Vauxhall Insignia / Astra AF40 / AF50 6-speed auto
How P0734 is fixed
- Solenoid or rebuild
The P0734 misdiagnosis that wastes money
Do NOT let a garage sell you a rebuild before these three checks. One — when was the ATF last changed? On any auto/DSG the fluid is service-critical (unlike what dealers used to claim). If it's over 60,000 miles since a change (or ever, in dealer 'sealed for life' cars) get a proper drain-fill with correct-spec fluid before anything else — 4 in 10 P0734 codes clear on fluid alone. Two — read live shift-solenoid data. If solenoid B or D is showing high resistance or stuck duty cycle, it's a £180–£380 solenoid pack, not a rebuild. Three — on VAG DSG / Ford PowerShift, get the mechatronic serial number and check it against known-failure batches; on BMW ZF the sump-gasket-and-filter kit (£220–£380 fitted) fixes half of all 4th-gear codes because the internal filter blocks and starves the solenoid pack of pressure.
What a UK garage should charge for P0734
Diagnostic + live solenoid trace £70–£140, ATF drain-fill with OE-spec + pan gasket £180–£380 (BMW ZF, VAG DSG, ZF 6HP), solenoid pack replacement £280–£620 fitted, mechatronic recon (DSG) £850–£1,600 exchange, full gearbox rebuild £1,800–£3,400+. Labour From £70/hr. Warranty-safe: never let a garage 'flush' a high-mileage auto with a pressurised machine — that dislodges clutch debris and can kill the box.
P0734 repair cost in the UK
Most P0734 repairs land between £250–£2500 including parts and labour. The spread is wide because the cheap fix (a sensor, a hose, a leak) and the expensive fix (a major component) throw the same code — which is why a proper diagnosis before parts are bought saves the most money.
Bob's tip on P0734
Ford PowerShift DPS6 dry-clutch boxes are a known-flawed design — Ford extended the warranty on many. If your Fiesta/Focus PowerShift has a P0734 with judder, check whether your VIN is still in warranty extension before spending a penny privately. On BMW ZF 6HP a Mechatronic sleeve failure is famous — the plastic sleeve at the pan connector cracks and lets fluid leak internally; £90 part, but must be done as part of a fluid + filter service. On VAG DQ250 (wet DSG) always change the fluid AND the filter at 40k intervals — dealers who tell you 'sealed for life' are wrong for the UK's stop-start driving. <a href="/ask-a-mechanic-uk?code=P0734">Ask Bob about your P0734</a> for £14.99 with make, model, gearbox type, mileage and ATF service history — you'll know whether it's a £280 fluid service, a £480 solenoid pack or a genuine rebuild.
Can you drive with P0734?
Book in.
Urgency: high.