P0734

Gear 4 Incorrect Ratio

Q: Is it safe to drive with P0734?

Brief gentle driving may be okay, but slipping generates heat that accelerates wear and can ruin the transmission. Have it checked soon and avoid heavy loads.

Q: Can I just clear P0734?

It clears, but returns as soon as the ratio error recurs. Start with fluid and solenoids; ignoring persistent slipping leads to expensive internal damage.

Transmission Generic OBD-II High

What it means

P0734 means the transmission calculated the wrong gear ratio in 4th gear — the input and output shaft speeds don't match what 4th should be, which usually indicates slipping. Common causes are low or worn-out fluid, worn clutches, or a shift-solenoid/valve-body fault. It is a transmission fault, not an engine no-start; but continued slipping builds heat and wear, so it should be addressed promptly.

High

Can I keep driving? The transmission may slip in 4th, rev without gaining speed, or drop into limp mode — driveable gently, but continued slipping causes heat and wear, so fix it soon.

Real-world scan data

Seen in

263

scans in the past year

Found in

<0.1%

of scans

0.1%

of scans that found faults

Appears alongside · share of P0734 scans

P0732in 65.8% of scans

P0733in 65.8% of scans

P0731in 59.3% of scans

Figures reflect only diagnostic scans recorded through our own apps and tools. Cars are typically scanned because a symptom or warning light prompted it, so these counts describe our scan records — not the incidence of faults in any model, and not the quality, reliability, or safety of any vehicle. No comparison between manufacturers or models is implied. All trademarks belong to their respective owners; no affiliation or endorsement is implied.

Common symptoms

What you'll notice

Check-engine light on (sometimes a transmission warning light)
Slipping in 4th gear — engine revs climb but speed doesn't follow
Harsh or failed shift into 4th, or falling back out of it
Limp mode and, over time, transmission overheating

Common causes

Most likely first

Low or degraded transmission fluidLikely
Worn clutches or bands slipping under loadCommon
Faulty shift solenoid or a valve-body faultCommon
Speed-sensor signal error, or less commonly a failed torque converter or TCMLess often

How to diagnose & fix

Work through it in order

Scan and record freeze-frame data, and compare input vs. output speed to confirm the ratio error is in 4th gear.
Check the transmission fluid level and condition first — low or burnt fluid is a common and cheap cause.
Test the shift solenoids and inspect the valve body for sticking or a stuck valve.
If fluid, solenoids, and sensors are good, the internal clutches or torque converter are likely worn and need a transmission specialist.

FAQ

Quick answers

Is it safe to drive with P0734?+

Brief gentle driving may be okay, but slipping generates heat that accelerates wear and can ruin the transmission. Have it checked soon and avoid heavy loads.

Can I just clear P0734?+

It clears, but returns as soon as the ratio error recurs. Start with fluid and solenoids; ignoring persistent slipping leads to expensive internal damage.

Read & clear P0734 yourself

Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.

▶ Get it on Google Play

✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX