I have a friends car that just got dropped off to me for a VTEC error code. I went to check for power at the plug and it's only getting .04v. I know I need to troubleshoot down stream so I'm thinking just going to the ECM to test the pin. Not sure or not but I think it is the A4 pin that needs to be checked. Question:

1. If I'm not getting 12v at the ECM with the ignition on I need to change the ECM. Are these just plug and play ECMs?

2. If I'm getting 12v at the pin then it means the ECM is good and I'm looking at replacing the wiring upstream. How would you go about doing it?

I know I have over simplified this but looking for a more knowledgeable person to answer so when I work on it tomorrow I can get it done and out the front of my yard.

 

Depends if you checked the solenoid or the pressure switch. The pressure switch should get a 12V with the engine running and probably with the key in just the II position. The solenoid will only get power when vtec is engaged.

The PCM has an imobilizer, so you would have to program keys if the pcm is suspect and you have to replace it.

 

You know I was waiting for you to respond. Lol

With the key at the II position the oil switch gets 12v and VTEC only gets .04v. With me monitoring (via LAUNCH tool) the VTEC it does not switch on when it should (during a drive). The solenoid does work as it should when I tested it.

Now that you have given me this insight i will hook my computer up to PCM side to see if it's providing the voltage at 4K RPM and that should let me know if it's the PCM or wiring. If it's the PCM I hope my tool can program the keys.

 

Update: I did more testing and the PCM is not sending voltage to the solenoid (still .05v when it should be switching). So I've purchased a used one hoping my Launch can code the key. I will update towards the end of next week once I get it put back together.

 

Final Update: the problem has been fixed with a new ECM. I put it in last night and thank god my Launch was able to program the key.

The car also had an issue with the rear brake lights not working (rear brake lamp on dash was on) and the SRS light being on. It was weird because the third brake light worked fine and after doing some electrical troubleshooting I gave up. Then I focused on the SRS light. Apparently the car was in an accident and that's why it was on. I did a reset and initialization on the system and the light went away. Then I noticed the brake lamp light went away also Checked the brake lights and they were working now. So I'm only assuming that when there is crash data on the SRS module the brake lights don't work (I really don't know this for sure). The Launch tool I have was a great buy and I'm not regretting the price at all.

 

I am back with this issue again on the same car. Almost 3 months and it was working fine. I am at a lost now what to do next. It's had an oil change, new VTEC solenoid assembly, used ECM put in (both perform the same way). I'm getting voltage and that is what is so puzzling. I've attached the codes and data stream.

When I first got the car the CEL would come on instantly after it was cleared now it doesn't. The solenoid will engage a couple times then throw a the CEL. I know there is something I'm missing. If anyone has any ideas I'm all ears.

 

One funny thing is P1279 isn't in the code list from the 1998-2002 FSM. P1259 isn't very descriptive.

The VTEC oil-pressure switch is a kind of feedback that the spool valve is actually working. I THINK(?) that each time the PCM sends a command to the VTEC solenoid, you should see a resulting signal from the VTEC oil-pressure switch. And nothing. It looks like after 2 attempts, the PCM gives up & sets the error code.

Have you verified the wiring to the VTEC solenoid and from the VTEC oil-pressure switch is OK? The plots show that the PCM sent the signal, but maybe the solenoid isn't actually operating?

Have you taken off the spool valve & cleaned it up? Screens maybe clogged? Maybe you can figure out some way to apply pressure to the VTEC oil-pressure switch and check that it responds?

 

After reading back through the thread, here's a couple more thoughts...

You mention an accident. What about additional flaky connections in the wiring for the VTEC system that has now finally come loose?

When you got a new spool valve, did it have the oil-pressure switch? Or did you have to install your old switch?

 

Turns out that is wasn't in an accident. The seat belt buckle was damaged giving the code as if it was in an accident. I purchased a new spool assembly with switch twice. I verified that it works. I'm going to relook at some wiring today to ensure my wiring job didn't mess up.

 

The switch I have wired as a constant on. It would not switch when wiring it up the correct way. That is what made me change the ECM. I will wire it back the correct way and test to make sure I'm getting 12v at the plug. I may try another ECM just for the practice (lol). I'm just out of thoughts on this one.

One thing I didn't check was to see if the port was plugged up where the spool hooks up to