Blazer p0740 help

[FishFind]

I have found many threads on this problem but not really anything on how to find the problem. I know it is TCC solenoid. Everyone it telling me to check the wires first before getting a new solenoid but how? do I use a volt meter? What readings am I looking for? Also some of the threads say something about the ignition switch?

[MT-2500]

Originally Posted by FishFind

I have found many threads on this problem but not really anything on how to find the problem. I know it is TCC solenoid. Everyone it telling me to check the wires first before getting a new solenoid but how? do I use a volt meter? What readings am I looking for? Also some of the threads say something about the ignition switch?

The good repair manuals and programs have repair flow for codes.
That lead you threw the proper test for any and all codes.
Usually they require a good engine capable scanner and a good new type volt/ohm meter.
Use care in testing computer voltages.
The old type resister volt meters can wipe out a computer.
97 is a bad year for ign switches.

And yes always check wiring and plugins voltage readings and do not forget grounds.

[FishFind]

The odd thing is that from what I have read the CEL whould not go on untill the tcc attempts to engage at 40mph.
On my car the code comes on within 5 seconds of starting the car, even after it was cleared. Never shift out of park.

[4x4 blazerguy]

There is no REPROGRAMMING KIT, & No it is not a spacer. The problem is the Torque Converter has limited oil flow. As the Valve body wears valves leak by decreasing oil to the converter. The reprogramming increases the flow to the converter & fixes any valve leaks. Mine did the exact same thing as yours. Never got it into gear & the CEL came on. Take it to a good tranny shop & if they don't know what I'm talking about then find a shop that does. I had Team Ramco do mine. They are in Yuma AZ but started business in the San Diego area. I never even finished describing the problem when they told me the code it was throwing & that if the converter wasn't burned up they had a permanent fix. It cost me $350 with a complete service & a 90 day unlimited warranty. It was worth every cent. The tranny shifts way better than it ever did. Even my wife noticed a big difference. Overdrive is now even a solid shift.
Why mess with something when you don't have the experience or equipment. I'm an old retired mechanic that knows he is not up to date on many areas of the computer vehicles.

[MT-2500]

Originally Posted by FishFind

The odd thing is that from what I have read the CEL whould not go on untill the tcc attempts to engage at 40mph.
On my car the code comes on within 5 seconds of starting the car, even after it was cleared. Never shift out of park.

When the ign is turned on and or engine is started the VCM computer checks things out.
If it finds a problem it may turn on check engine light and set a code for the problem found.
In you case.
Code P0740 is telling you there is a open or short to ground in the TCC solenoid circuit.

You need to repair the circuit or TCC solenoid.

[FishFind]

mt-2500 Do you know what wires to check?? I know what wire it is on the wire harness plug at the pan but I am unclear where it goes back towards the engine.

[MT-2500]

Originally Posted by FishFind

mt-2500 Do you know what wires to check?? I know what wire it is on the wire harness plug at the pan but I am unclear where it goes back towards the engine.

It goes from transmission plug to VCM.
As in circuit there is hot and ground or return.
Making 2 wires to check.
Is it going from plug in to TCC solenoid and back out og TCC solenoid?

Year Make and Model and Engine and Transmssion 2 - 4 W?

[FishFind]

1998 chevy blazer 4.3L 4wd push button
Internal wires are good they are new. I tested the TCC with a battery before I installed it.
I am guessing the red /hot power wire is good because I don't get any other codes but the p0740
I unplugged the VCM and connected a volt meter to pin 10 on blue harness I connected the red wire from volt meter to the batt and black to pin 10 with the wire harness unplugged. I got 0v. If i GROUND THE TCC WIRE ON THE WIRE HARNESS AND TEST IT i GET BATT POWER. I don't think it is grounding or broken.

[FishFind]

Well CEL back on. Never even drove it. I did notice one thing though. When the key is in the on position but not running no lights are on except the gauges. I start the car and no lights come on untill about 6 seconds later and then all the lights come on. E.G. check engine, airbag, check gauges etc. On my s-10 all the lights come on when key turned not started and then stay on for about 3 seconds after I start it and go off.

[MT-2500]

Originally Posted by FishFind

Well CEL back on. Never even drove it. I did notice one thing though. When the key is in the on position but not running no lights are on except the gauges. I start the car and no lights come on untill about 6 seconds later and then all the lights come on. E.G. check engine, airbag, check gauges etc. On my s-10 all the lights come on when key turned not started and then stay on for about 3 seconds after I start it and go off.

I would get a repair flow chart for the code and go all of the way threw it.
Also check ign switch power feed circuit.
97 and up into 98 had a lot of ing switch problems.

[FishFind]

Ok all the flow chart is ok from what I can tell. Here is the other stuff. The air bag light is on random sometimes on sometimes off. Also the key is very hot after I take it out. Even if just in for 30 seconds.

[MT-2500]

Originally Posted by FishFind

Ok all the flow chart is ok from what I can tell. Here is the other stuff. The air bag light is on random sometimes on sometimes off. Also the key is very hot after I take it out. Even if just in for 30 seconds.

As in post 10 check that ign switch.

[FishFind]

I know this is a old post but I did fix this problem. I do not have the time to write up a long story on what I did to check and fix it but if anyone has the same issue on a blazer or s10 PM me and I can walk you through everything you need to do from start to finish it fix it.

[MT-2500]

Originally Posted by FishFind

I know this is a old post but I did fix this problem. I do not have the time to write up a long story on what I did to check and fix it but if anyone has the same issue on a blazer or s10 PM me and I can walk you through everything you need to do from start to finish it fix it.

That is a sad excuse.
After all of the help you got on here and the time we spent trying to help you.
You are now a expert repair person but never say thanks or a hint as to what your problem was so that it may help others.

[FishFind]

ok,ok.
I will try and write something up here soon. Hard to find time with the little ones.