P0735
UniversalThe Powertrain Control Module (PCM) or Transmission Control Module (TCM) has detected that the actual gear ratio of the transmission is not matching the desired gear ratio when 5th gear is commanded.
High SeverityThis code indicates that the Powertrain Control Module (PCM) has detected that the actual gear ratio of the transmission does not match the desired gear ratio for 5th gear. This typically means the transmission is slipping or not engaging 5th gear properly, leading to reduced fuel economy, lack of power, and potential severe transmission damage if ignored.
⚠️ Before You Begin (Safety First)
Always ensure your vehicle is on a level surface and the parking brake is engaged before working on it. Allow the engine and transmission to cool down completely before attempting any work. Disconnect the battery before inspecting electrical components to prevent accidental shorts or injury. Transmission fluid can be hot; use appropriate protective gear. If the vehicle exhibits severe symptoms like harsh shifting or grinding, do not drive it.
Common Symptoms
- Check Engine Light illuminated
- Transmission slipping
- Delayed or harsh shifting
- Vehicle stuck in a specific gear (limp mode)
- Poor acceleration
- Reduced fuel economy
- Unusual noises from the transmission
- Vehicle not engaging 5th gear
Common Causes
- Low or dirty transmission fluid
- Faulty shift solenoid for 5th gear
- Internal transmission mechanical failure (worn clutch packs, broken bands, damaged gears)
- Faulty Transmission Control Module (TCM) or Powertrain Control Module (PCM)
- Clogged transmission fluid filter
- Faulty transmission speed sensor
- Wiring or connector issues to the transmission or solenoids
Frequently reported on: Honda CR-V 2007-2011 (Automatic Transmissions), Nissan Altima 2007-2012 (Traditional Automatic Transmissions, not CVT), Ford F-150 2004-2008 (Automatic Transmissions), General/Universal
Diagnostic Steps
- Check transmission fluid level and condition: Ensure it's at the correct level and isn't burnt or discolored. Top off or replace if necessary, following manufacturer specifications.
- Inspect transmission for external leaks: Look for any fluid leaks around the transmission pan or lines.
- Inspect wiring and connectors: Visually check for any damaged, corroded, or loose wiring and connectors leading to the transmission and its sensors/solenoids.
- Clear the code and test drive: After performing basic checks, clear the code with an OBD-II scanner and take the vehicle for a test drive to see if the code returns or symptoms persist.
- Consult service manual for specific diagnostic procedures: If the code returns, refer to your vehicle's specific service manual for detailed diagnostic steps related to the transmission and shift solenoids.
👨🔧 When to Call a Professional
If after checking basic items like transmission fluid level and condition, the P0735 code persists or symptoms like harsh shifting, slipping, or grinding worsen, it is time to consult a professional transmission specialist. Internal transmission issues or complex electrical diagnostics are best handled by experienced technicians with specialized tools.
Commonly Asked Questions
What specifically does P0735 mean for my transmission?
P0735 indicates your vehicle's computer detected that the transmission's 5th gear ratio is incorrect. This means when the vehicle tries to engage 5th gear, the transmission output speed doesn't match what it should be for the engine speed, suggesting slippage or improper engagement.
Can I continue driving with a P0735 code?
It is not recommended to continue driving with a P0735 code. Ignoring it can lead to further, more severe internal transmission damage, which can result in very costly repairs or even a complete transmission replacement.
Is P0735 always a sign of a bad transmission?
Not necessarily. While it can indicate significant internal transmission wear, it could also be caused by simpler issues like low or dirty transmission fluid, a faulty shift solenoid, or a problem with a speed sensor or wiring. Proper diagnosis is crucial.
What are the first steps I should take to diagnose P0735?
Start by checking your transmission fluid level and condition. Ensure it's full and not burnt or dark. Also, visually inspect all wiring and connectors to the transmission and its solenoids for any damage or corrosion. Clearing the code and test driving can help determine if it's an intermittent issue.
How much does it typically cost to fix a P0735 code?
The cost varies widely. A simple fix like topping off fluid or replacing a faulty sensor might be inexpensive ($100-$300). However, if the issue is a failed shift solenoid, it could range from $300-$700. If it's internal transmission damage, costs can escalate significantly, often running into thousands for a rebuild or replacement transmission.