I have a 94 Accord LX that is giving me fits with a D4 code of 10 (one long blink) and a 13 (one long, and 3 short blinks). Code explanation is supposed to be Coolant temp sensor O or S for the 10, and Main shaft speed pulse generator for the 13. I have replaced the TCU, Lockup solenoids, VSS, both the speed shaft pickups, and the temp sensor I replaced was the coolant gauge sensor. I just really don't think its the coolant temp sensor, but am looking for any input I can get. Please help before I lose my mind

 

The issues can be the ECT sensor, wiring, ECM, etc.

The ECT sensor has the 2-P connector with the Red/Wht and Grn/Blu wires which respectively route through other separate junction connectors in the engine bay and eventually go the ECM (at the 22-P grey connector - C460). It can be the ECT sensor, connector, short or open in wiring, or ECM related to the Code 10.

For the Code 13, it can be a short or open in the Blu/Wht wire going from the TCM to the ECM or a problem with the ECM. Check the connectors too.

The Blu/Wht wire goes from the TCM (22-P grey connector - C461) to the ECM (22-P grey connector - C460).

In addition, just for good measures, check the the G101 ground wire connection used by the both the TCM and ECM is clean and solid on the intake manifold.

 

Thanks for the reply. One more symptom that may be important,when I start the car cold that is when I get the D4 flash. I can let it idle for 10 minutes, drive it 1 mile shut the car off and turn back on,it self checks and the code will stay clear most of the time while continuing to drive. The transmission shifts as it should then. But at cold start up, and D4 on it will act like it is trying to start off in 3rd or 4th gear. I know with the cold start code that tends to make you want to lean towards the ECT sensor, but would it not through the CEL as well?

 

The ECT may not be working properly and it may not illuminate the Check Engine Light or even throw a trouble code; there have been reports of that. The ECM may think it is fine.

In your case, you seem to have the code 10 from the D4 to indicate a possible problem with it.

 

Roger that. I'll change the ECT sensor and give it a try. I will post my findings Thanks for your help

 

Redbull-1, it was the ECT. I changed it and the plug, both plugs cleared and all is well. Thanks again.

 

You're welcome and thanks for reporting back the issue was resolved.

 

Well my daughter drove the car all weekend,and all was well. On Monday she started the car and it coded again, with the same symptoms, (drive for about a mile, shut it down and the codes cleared). I pulled the codes, now I am getting a 8,10,and 13. I have replaced the lockup solenoids, ECT sensor, TCU, and main shaft pickups. I have also checked the plugs in the engine bay as well as the intake ground. I have not pulled the ECM and TCU and checked the connections and continuity between the wiring and pins you had pointed out. Do you think its a wiring issue or can the ECM have these come and go malfunctions?

 

The code 8 (if it is from the D4 indicator) relates to the Shift Control Solenoid Valve B.

Attached is the Code 8 Diagnostic troubleshooting. It states various things to check such as the wiring, TCM connector and the solenoid. Make sure to check the connector between the TCM and ECM.

With the various codes, it could possibly point to the TCM; but, you already replaced that. There could be a communication problem between the TCM and ECM, so double-check the wiring harness connector between them.

ECM is a possibility; but, check wiring first.

 

In checking the light green/ black wire between the ECM and TCU I only have 1.5 to 2.2 volts at any given time coding or not. In some of my troubleshooting yesterday I tried an experiment: When I turned the ignition on,with the car cold, the car self checked, CEL went off, D4 went off, and 30 to 45 seconds later the D4 coded 8,10,&13. I let the car sit for exactly 20 minutes with the ignition switch in the on position. I then turned the ignition switch off, and back on all codes were gone. Note the car was never started, and the ambient temp was 90 degrees. We then drove the car with no events. I have checked all the wiring for continuity between the ECM and the TCU and their respective sensors. All the connections seem tight. The only thing out of the ordinary is the 1.5 to 2.2 volts on the light green/black signal voltage wire, that on the drawing you sent shows 5 volts. Commonly on the equipment that I work on, that big of a voltage problem would be a bad ECM. Your thoughts?