o/d light wont light

[1S9H9O5Ford]

I have searched first but no specific fix for my current problem. I have a 1995 with no o/d light on start up or during drive. Push the tcs(o/d) button and no change in rpm or light. I know light is good swapped with trans temp light next to it and back and lights both good. Codes pulled and 326,335, 628. Car running rough but hasn,t been driven for awhile. I have checked the wire from the computer harness to the pin on trans plug and 0 ohms reading through the wire. The wire for the shifter switch checked and not broken. Even tried a second shifter same thing. 106,000mi on car. Help! PLease! I don't want to pull side pan want to exhaust all avenues first.

 

[projectSHO89]

There's nothing in or near the transmission that controls the TCIL. It's controlled by the PCM based on the logic and the operation of the TCS.

Run the KOER codes, also, as it includes a test of the TCS.

 

[notbange]

Overdrive off wires coming out of the shifter are probably broken.

 

[1S9H9O5Ford]

Thanks I will try this in the morning.

 

[1S9H9O5Ford]

Checked codes KoEo:335,173, 177. KOER:412, 326, 412, 173, 326. Drove car for 20min to store and back before testing. Smells like it is running rich. Hope y'all can help!

 

[1S9H9O5Ford]

Update

Did trans drive cycle test today and 628 code. Never get a o/d light on dash pushing button or not. The wires in the shifter are not broken. Could it be the pcm. The sticker on the pcm is 4wlo,and Ez27 are these even sho computers. May be reason light won't come on. I am working on fixing the other codes but want to get trans fixed too.

 

[rubydist]

335 - dpfe sensor voltage higher or lower than expected - this could be wiring or could be the sensor itself. start by checking connections and wires.

173 - rich on right (rear) bank. this is typically a bad o2 sensor.

177 - rich on left (front) bank. this is typically a bad o2 sensor.

the fact that you have both showing rich could also mean that you have a mafs that needs cleaning (unlikely, since they usually read too little air rather than too much air when dirty) or that you have leaking fuel injectors (don't shut off properly).

412 - cannot control rpm during high speed portion of self test. this is usually either a sticky iac or a bad vacuum leak or a combination of those. given your other issues, it is more likely a bad iac.

326 - dpfe voltage lower than expected. see above.

628 - excessive torque converter clutch slippage. normally when this occurs, you will get a flashing o/d light on the dash. in my experience, it will slip sometimes and lock up most of the time in the beginning, and then gradually get worse. the only solution for this is to replace the torque converter.

 

[1S9H9O5Ford]

It has a new dpfe one of the vacume hoses came off(was replaced before I got the car). O2 sensors from a donor car Bosch appear fairly new. Donor a wrecked 1995 with 89000mi. Could the light not comming on be from the torque converter slipping or from the selenoid being bad?

 

[projectSHO89]

Could the light not comming on be from the torque converter slipping or from the selenoid being bad?

No.


Since the KEOR test didn't give a 632 code during the dynamic test, the TCS and the shifter harness are okay. Check continuity of the harness from the cluster to the PCM to see if it's okay.

 

[rubydist]

I agree, the koer test not returning a code for lack of o/d button pressed suggests that the o/d off switch is working, just the cluster is not getting the message to light the o/d off light. this can be tested by driving the car at freeway speed and pressing the o/d off button - this should result in an obvious downshift and resulting significant increase in engine rpm. this will confirm that the button is working fine, just the light not illuminating.

the fact that the o2 sensors "appear fairly new" means absolutely nothing.

your dpfe issue is probably wiring related.