94 PAU checking engine codes question

[Cntrysthbst]

Got a 94 the has the OBD 1 computer and the OBD 2 termial, is there a way I can check the codes without buying the scanner? can I jump anything? thanks for the help, HotZ you have answered this for me already but cant remember, sorry . Thanks again! Rob

[HotZ28]

Hello Rob, yes we did discuss this once before, Click Here

[Cntrysthbst]

read the whole thing, thanks, now can I jump the OBD ll being it has a OBD l comp. to check for engine codes? like on the OBD l term? Or do I need the scan tool? Thanks again

[Bassasasin]

Originally Posted by Cntrysthbst

read the whole thing, thanks, now can I jump the OBD ll being it has a OBD l comp. to check for engine codes? like on the OBD l term? Or do I need the scan tool? Thanks again

My auto parts store.. O'Reiley's, where I BORROW the readers, bought a new kit because their old loaner kit was getting tired and forgot about "our special cars".. Now I visit Autozone and borrow theirs.
I understand OBD1 codes can be checked by shorting pins in our OBDII connectors and counting flashes... Auto parts stores often have that "Special" adapter connector added in their kits for this specific issue of an OBDII connector with an OBDI PCM.

Your choice, I kindof like to see the reader do it because I cant count and the store is convenient.

P.S. The codes may show an error.. your error is only indicating it saw an issue. Many have bought the indicated errors replacement sensor only to discover later another related issue repair. Just be aware, more often having the code reader at the stores to loan out makes them some extra bucks .


Good Luck...

[Cntrysthbst]

No luck on the stores having that part,

is there any way to check the computer at all even though its still an OBD 1 computer? with out buying a scanner of course, does anyone know what the terminals with wires to them go to and or what they are used for? that is for the type 2 term with the OBD 1 comp, thanks again!

[HotZ28]

If you have a laptop, you may want to get This Cable and some free compatible software also found there.You particular car should have # 16183247 ECM/PCM with a #16067633 : 27C512 32K*8 EPROM

I don’t think you would have one, but you can check under the hood for an OBDII compliance sticker.

[Cntrysthbst]

Thanks, I finally got the code from a repair shop, it is code P-705, I believe it's a transmission code, maybe a switch, is this possibly located on the outside? can you explain more on this please? Thanks again for all your help!

[HotZ28]

P0705 = Transmission Range Sensor Circuit malfunction (PRNDL Input)
The PRNDL switch is located on the manual shaft lever and it gives transmission range based on lever position. It inputs the selected transmission range into the PCM and controls shift solenoid state. It is an assembly of four switches that connect to ground.

The diagnostic mode detects the 9 false combinations & checks the P/N discrete on starting or in forth gear. The transmission failsafe mode is; Uses the D4 shift schedules & the TCC PWM solenoid will be regulated incorrectly in D3. These defaults will recover when a valid range is detected.

Problems usually associated with the PRNDL switch are; if not properly aligned between D3 & D4, no TCC may occur and will set a code. In addition, if not properly aligned, or in wrong range, manual low may not be available or attainable. Do you have either of these indications?

[Cntrysthbst]

Hmmm, I honestly don't know. I have noticed a difference in the shifting, not slamming but shifting prematurely, sometimes when I come to a stop and the transmission is shifting down the lights and volts go dim and slowly back up. Just replaced the alt. again and checked all grounds, sometimes when I let off the gas it does it as well(voltage) when tapping the brakes alittle, this started happening when I got this code. The transmission started acting strange at the same time. I noticed sometimes when I let off the gas the transmission is in the wrong gear untill I hit the brakes, hope this helps, thanks!

[HotZ28]

Your problem could be surging high/low voltage. The PCM, sensors, solenoids, fans etc; all depend on steady reliable voltage feed. You said that you checked all the grounds and that is good, however, steady positive feed is actually more critical.

Recently on my 94 LeSabre, I had voltage spikes as high as 18v and as low as 10v at random times. After cleaning all the cable connectors on both sides, it worked better for a few weeks, and then the problem returned. I knew that the alternator was not the problem! I eventually had to cut the insulation off my positive cables to uncover a hidden corrosion problem that was causing the problem. Remember, the alternator voltage feed wire is crimped to one of the positive battery cables. This is where the problem lies on the majority of the high/low voltage problems on these cars with the dual positive cables.

I purchased some new terminals at a local audio shop and soldered the wires to the terminals. I also purchased & installed a 'gold plated' battery post that screws into the battery with a male threaded terminal & nut for mounting the wire terminals. After all this was installed, my voltage is steady @14.2v with the engine @ idle & battery voltage @ 12.67 engine off. The lights are brighter, the AC fan runs faster and very little fluctuation in voltage with all accessories on, with turn signals applied.

Try to get steady voltage on your car first and then see if you have any other problems.

Oh, one other thing I did; installed a copper washer between the two positive cables for better contact.

[Cntrysthbst]

That is just some excellent info, am going to do this today and let you know...thanks