Hey guys. First I want to say I am new to Honda but new to working on cars. With that out of the way, I picked up a 90 accord automatic. It ran a little rough when I got it so I started to do some tune up stuff. I replaced spark plugs, plug wires, valve cover gasket belts and hoses are recently replaced as well. Cap and rotor looked good as well.

The car has the s light blink from the time i bought it, I jumped the diagnostic plug to see if there was a code. It looked to be code 7 - TPS. I tested the TPS and it seemed ok but went ahead and replaced it with a new one. The car seemed to shift hard from first to second and very sluggish after first. After replacing the TPS there was no change, the light is still blinking and the the code is still saying 7. I was also seeing some random Speedo and Tach not working, so I picked up a couple speed sensors from my u pull it. The shifting was a little smoother first to second but still no change with code and power. You can push the petal to the floor once it's in second and it's like a GEO metro with a 3 cylinder engine (just nothing moving quick at all). Now in the process of everything my shifter is stuck in park. I have to use the shift lock release to move it.

Any idea what I am facing here?

 

The S light indicator blinking means it is transmission related. Many Accords for your generation Honda had problems with the Transmission Control Units (TCU). You might want to pull it out and open it up to check for burnt resistors and/or capacitors. Code 7 from the S light is not the same as Code 7 if it was the Check Engine Light blinking.

 

Thank you I will work towards pulling the TCU and will update the post as soon as I can.

 

OK I have pulled the TCU and took it apart, I can not see any burns on the circuit, front or back and all caps seem to be fine. I did verify before disconnecting the battery, the TCU is giving the same code 7 as noted on the diagnostics for the s light. I have found an article that someone stated they had the same code and it was their connection at the shift solenoid. I am going to check this, but if there is anything else I should check please let me know and I will do so.

Thank you,

 

TCU is reinstalled and I have tested both solenoid packs, the lock out solenoid (upper pack), and the shift solenoid (lower pack), using a jumper from each prong to the + post on the battery. All 4 solenoids click, the lock out solenoids clicked quite a bit stronger then then shift solenoids. I am still seeing the 7 blinking lights at the TCU when the car is in the on position. Somewhere I read some said 7 was the shift solenoid. If I am getting a click when testing them how can I test the connector that goes to them from the cars harness? Should it be a specific voltage when the key is on? If I completely unplug the shift solenoid and still get the same code is that strong enough to say that is the issue?

I also tried to do each gear manually, but it is freezing here (literally) so the car wasn't warmed up yet, 1st to D4 and noticed that 1,2,3 all seemed to have some power but 4 was a turd. I also noticed all the gear indicators work except D4 it does not illuminate. I know it could be a bulb since this is the most used gear but is there anything else that could be a symptom of?

Thank you again for all advice.

 

I'm not the best at the electrical side, could someone clear this up of me. When the below says to measure the volts between A25 and A5 am I supposed to make a jumper and probing the jumper to test for voltage?

 

What it means would be to use a voltmeter; touch meter's red lead to terminal no. A5 and the meter's black lead to the terminal no. A25 of the TCU. Measure the voltage.

 

Ha that makes more sense. Thank you for clearing that up

 

Sorry for the delays. We have crappy weather lately so I haven't spent much time on the car. I took it out today for a little test drive again, the car didn't feel like it wanted to shift with out me manually shifting it. It hit high RPM's in first gear but didn't want to upshift. I stopped at the store then fired it up and took off again. Low and behold the blinking S light stopped blinking, the sport button worked again and all the sudden the car shifted through all gears. BUT once I put it in reverse it when right back to the same issue. I am still going to replace the shift solenoid, but should I or do I need to replace the lockout as well?

 

Sounds more like a wiring issue than a trans or TCM issue.
If the problem showed up after bad weather, most likely an issue with wiring grounding out, shorting out, or moisture/corrosion at the connections. Maybe even a loose/backed out pin.
Also verify that your shifter cable and gear selector switch are properly adjusted and not full of crud.

Usually multiple electrical failures are not due to a failed component(s) but failing/failed wire/connections.
TCM commands shifts. If it doesn't command a shift, the trans won't shift.

If the engine is in poor running condition(chucking codes), and it may not even feel like it, this will greatly affect how the transmission functions.
A bad TPS will not allow for upshifts as the TCM also monitors several engine sensors in order to shift correctly.
If you still have a TPS problem, find out why you have a TPS problem. We know it's most likely not the TPS sensor itself, check the wiring, check the engine harness, check the ECM harness/connections. Verify all the grounds are good and intact as well as the wire harness.