Hello. First post here. Tried to search, but couldn't get to the bottom of the issue, so here goes...

I have a '96 Accord LX, 4-cylinder, automatic with about 190k miles.

Yesterday my girlfriend called me while driving to say the CEL light had come on and the D4 light was continuously blinking. She also described the car not wanting to go into 4th gear as she was approaching 65-70mph. Other than that, no other issues were reported and she made it home just fine.

In investigating the problem, I found some info on how to jump the ECM plug and check the diagnostic codes. In doing so, I got a CEL code of 70- "Automatic Transmission malfunction with the automatic transmission controls," and an Automatic Transmission Diagnostic (D4) code of 9- "NC speed sensor." I did find this page with diagnostic help, but since I am not well versed in car repair work, I'm a bit lost: http://techauto.awardspace.com/transmission.html

Before I take my car to a mechanic, can anyone shed a little light on what this all means, and perhaps translate these codes into english for me? Also, is the car safe to drive for a while, or should I get it to a mechanic ASAP?

Thanks in advance for any info you can give me. I really appreciate it.

 

You checked your car by the OBD1 method which gives some generic codes in some cases (the code 70).

The check engine code 70 is caused by a number of transmission (D4) codes, one of which is a code 9.

Code 9 which is the a problem with the counter shaft speed sensor. I will bet that if you went to an autozone and have the scan for codes with the OBD2 scanner, you would only get a code P0720.

You probably have a bad sensor that needs to be replaced, or a loose/dirty connection. You can check the resistance across the two pins of the sensor and it should be between 400-600 ohms. The attached pic is looking at the transmission if you were standing at the passenger seat and looking to the front of the car.

 

Thanks PAhonda. That's quite helpful. From the description my girlfriend gave me, it sounds like the car might have gone into limp-home mode? In the middle of driving on the highway, it downshifted into 3rd gear and the CEL and D4 lights went on, and then would not shift back into 4th gear.

Assuming it's just the countershaft speed sensor which needs replacing, is the car safe to drive in the meantime? Is it ok to drive the car in limp mode (if it is infact in that mode)?

 

I think limp mode is designed to prevent damage to the transmission. I would not drive it too much, because the transmission will probably shift poorly.

It looks like the connector should be easy to access. I would unplug the connection and see if there is any oil in the connection. Test the resistance as well.

If you can easily access the sensor, it looks like it is only one bolt to remove it. The parts stores may call it the output speed sensor and a new on will probably run ~$100. A junkyard would be cheaper source.

 

Iv have the sensor you want...it help you save some money. I just have to pull it off the trans when I get off work 2marrow...PM me if interested.

 

I don't have a way to test the resistance unfortunately. I will unplug the connector and check it for oil and debris though. Thanks again.

I'll let you know if I need the sensor g22cd5. Thank you.