Jim Grant's Tech Tips
‘97 Mazda Protégé lx, Check Engine Light & Blinking Overdrive Light
Q: I have a ‘97 Mazda Protégé lx 1.5 liter. The problem is, as I’m going alongusually the first thing in the morning, my engine light comes on, then my overdrivelight blinks and the transmission shifts down “hard” by itself. Then when taking off, it shifts hard from 1st to 2nd then 3rd and will not shift into overdrive. If I go about 60 mph, then come to a stop at a light, the Overdrive light goes off then it shifts fine, but then I get a rough idle like it’s going to stall. I’ve changed the transmission speed sensor, like the garage informed me. But just 2 minutes and $300 after I got it, it shifted out of overdrive again, could it be an oxygen sensor? It’s driving me nuts and I need an honest opinion.
- Chuck Amerio
A: A Bad oxygen sensor? I doubt it. What you need is the code the computer is reporting. If you had a bad vehicle speed sensor the speed-o-meter would have stopped working and the computer would have been reporting a Diagnostic Trouble Code (DTC) P0500 for a vehicle speed sensor fault. You never stated that the speed-o-meter stopped working. When you have the computer checked and the DTC’s you get are P0710 or P0711 then you should be aware of a Technical Service Bulletin (TSB) from Mazda for a wiring problem. ALLDATA Information Systems shows Mazda TSB # 010/98 for a problem with the transaxle temperature sensor wiring being damaged and shorting to ground on the metal clips that guide the wiring. The result of this type of failure will cause the check engine light to turn on and the transmission’s overdrive on/off light to flash. The transmission will not shift correctly and it will shift hard. The computer codes will likely have the answer to your shifting problem even if the speed-o-meter is still working.