Troubleshooting Toyota Camry Transmission Problems

Transmission problems can be a serious—and costly—issue. Even before a transmission completely fails, poor shifting and unpredictable behavior in general can make your car or truck far less than a pleasure to drive. In some cases, a transmission problem can be traced to a minor issue, which means you can dodge paying a huge repair bill.

In the letter below, an owner describes his Toyota Camry's transmission issue. For cars built after 1998, a detailed trail of OBD (on-board diagnostic) codes is available, which is helpful in diagnosis. If you can't figure it out, you can go to the transmission shop, but it never hurts to get as much information on your own as possible before you hand the keys to somebody who is going to write an expensive repair ticket.

Question

I have a 1987 Toyota Camry. It has a 4-cylinder engine with automatic transmission and 285,000 miles. It has fuel injection, P/S and A/C. I've been having an intermittent problem with the transmission shifting. Most notably, sometimes when I pull out it shifts from low right into overdrive, and sometimes it won't come out of overdrive on the highway.

Sometimes I'll push the gas pedal to the floor trying to get it to "shift up" and it's like it comes out of gear altogether and the engine revs like it's in neutral. I just got it out of the transmission shop after having a partial rebuild and a rebuilt valve body put in it. I still have the same problem.

The transmission was completely rebuilt about 6 years ago. I've been told this could be a problem with a shift solenoid. Could it have anything to do with the engine idle being set too high? I would appreciate any advice you could give me.

Thank you,
Steve

Answer

The problem likely is electrical in nature, so the first thing you should do is see if any trouble codes are stored in the Transmission Control Module (TCM).

Here's how to read the diagnostic trouble codes from your automatic transmission:

Turn the ignition switch and overdrive switch to ON. Do not start the engine. The diagnostic code can be read only when the overdrive switch is ON. If it's OFF, the overdrive light will light continuously and will not blink, which is how you read the code.

Short the DG terminal circuit using a service wire; short the terminals ECT and E1. Read the diagnostic code by the number of times the OD "OFF" light flashes.

Diagnostic Code

If the system is operating normally, the light will blink for 0.25 seconds every 0.5 seconds. If there's a malfunction, the light will blink for 0.5 seconds every 1.0 seconds. The number of blinks will equal the first number of the two-digit diagnostic code and, after a 1.5 second pause, the number of blinks will equal the second number. If there are two or more codes, there will be a 2.5 second pause between each.

Remove the service wire from the DG terminal.

If several trouble codes are occurring simultaneously, the indication will begin from the smaller value and continue to the larger.

Codes 62, 63, and 64 appearing indicates an electrical malfunction in the solenoid. Codes won't appear if the cause is mechanical, such as a stuck switch.