P0730 Buick Code - Incorrect Gear Ratio
Quick Answer
This diagnosis monitors the actual gear position by checking the torque converter slip ratio calculated by the Transmission Control Module (TCM) as follows: Torque converter slip ratio = A x C/B A: Output shaft revolution signal from the speed sensor (revolution sensor) B: Engine speed signal from Engine Control Module (ECM) C: Gear ratio determined as gear position which TCM supposes If the actual gear position is higher than the position supposed by TCM, the slip ratio will be more than normal. Common causes include Low transmission fluid level, Dirty transmission fluid, Shift solenoids. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- P0730 Buick indicates Incorrect Gear Ratio.
- Common causes
- Common causes include Low transmission fluid level, Dirty transmission fluid, Shift solenoids.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Code P0730 Buick Description
Torque converter slip ratio = A x C/B
A: Output shaft revolution signal from the speed sensor (revolution sensor)
B: Engine speed signal from Engine Control Module (ECM)
C: Gear ratio determined as gear position which TCM supposes
If the actual gear position is higher than the position supposed by TCM, the slip ratio will be more than normal. In case the ratio exceeds the specified value, TCM judges this diagnosis malfunction.
The Diagnostic Trouble Code (DTC) will set when the TCM has detected that the transmission is trying to mechanically shift to a lower gear than intended.
What are the Possible Causes of the DTC P0730 Buick?
- Low transmission fluid level
- Dirty transmission fluid
- Shift solenoids
- Transmission mechanical problems
- Transmission hydraulic control circuit
How to Fix the DTC P0730 Buick?
Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.
Code Tech Notes
2000-2004 Buick Century
2000-2004 Buick LeSabre
2000-2004 Buick Park Avenue
2000-2004 Buick Regal
2003-2004 Buick Rendezvous
Buick Factory Service Bulletin OBDII Code P0730
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P0730 Buick code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.
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Frequently Asked Questions about P0730 Buick Code
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