P0736 OBD-II Trouble Code: Reverse Incorrect Gear Ratio

P0736 code definition

When the PCM stores this code, it means that the PCM has detected an abnormality in the ratio of a particular gear.

What the P0736 code means

The P0736 code is considered to be generic, in that it can occur in any make or model of vehicle made post-1995. Vehicles that are equipped with automatic transmissions use a torque converter to increase the output from the engine to the transmission, and drive the rear wheels.

A P0736 code is stored when the PCM identifies a problem with shifting into reverse, or driving in reverse. Various sensors within the PCM, ECM and TCM deliver identify slippage within the torque converter and the transmission speed sensor, and if the acceptable values do not match, then the DTC is set, and the Check Engine Light comes on.

Other codes associated with P0736 are P0730, through P0735.

What causes the P0736 code?

A P0736 code is stored when the vehicle delays shifting into reverse gear, or will not shift into reverse at all. This could be due to a problem within the transmission, but there can be other causes as well, including:

• A faulty shift solenoid
• Dirty or low transmission fluid
• A blockage in the lines that deliver the transmission fluid to the transmission

How does a mechanic diagnose the P0736 code?

The first step in diagnosing the P0736 code is to use a scanner to identify the code, and also to determine if any other codes have been stored. If there are multiple gear ratio codes, that usually indicates that there is slippage in the transmission. Next, your mechanic will:

• Check the dipstick to make sure that the transmission fluid is not low
• Look at the fluid to determine if it is clean
• Smell the fluid to determine if there is a burnt odor
• If the fluid smells burnt, remove the transmission pan to check for debris
• Check for burnt wiring and faulty circuitry
• Inspect the transmission to determine if damage has occurred that will require extensive repairs

Then your mechanic will do any maintenance that is necessary (topping up or replacing the fluid, for instance), and take your vehicle for a test drive. Upon returning, he or she will do another scan to make sure that the P0736 code has cleared. If the code does not come back, then there is a good chance that it was due to low or dirty fluid.

Common mistakes when diagnosing the P0736 code

The P0736 code can be difficult to diagnose, and in some cases, the problem may need to get worse before a proper diagnosis can be made. One of the most common mistakes in diagnosing a P0736 code is to assume that the problem is caused by a faulty shift solenoid. Then, solenoids are replaced when they are actually in good working order. Or, if the shift solenoids are working properly, a mechanic may assume that the PCM itself is defective. This is hardly ever the case.

How serious is the P0736 code?

You may not even notice any symptoms other than the Check Engine Light coming on, or you may find that you have difficulty getting your vehicle to shift into reverse. Sometimes, you may not be able to use the reverse gear at all. This is not a life-threatening situation, so you do not have to pull over to the side of the road and wait for a tow truck. However, because of the potential for serious damage to your transmission, you should get the problem taken care of at your earliest convenience.

What repairs can fix the P0736 code?

Most of the time, you will not need costly repairs – probably, all your vehicle needs is to have the transmission fluid replaced or topped up. Rarely, you may need to have a shift solenoid replaced. Even more rarely, the problem could be in the PCM unit itself, in which case it will have to be replaced and re-programmed.

Additional comments for consideration regarding the P0736 code

If your vehicle has high mileage, and the transmission fluid has never been topped up or replaced, this could be the reason for the P0736 code.

Need help with a P0736 code?

YourMechanic can send a certified mechanic to your home or workplace to perform any repairs that may be needed due to a P0736 code being recorded, or for any other reason. Just call us at 1-800-701-6230, or use our convenient online form to book an appointment. We’ll give you a free quote before we come out, and then we’ll get you back up and running.