Tach, TCS and shift issues

**Bob Savage** · 05-25-2007, 03:21 PM

So my wife ran my 98 WS6 out of gas and apparently, this causes the fuel pump to fail. The car wouldn't start so I had it towed to a show to figure out what was up and while it was there had them service the auto trans and differential. As a courtesy, they "steam cleaned" the engine (although I think it was more of a pressure clean than steam).

When I picked the car up today I backed out of the parking stall, put it into drive and it shifted into drive quicker than before and MUCH harder. I let them know this wasn't normal. I didn't notice it, but they asked me if the tach had worked previously because it wasn't working either (they could read the rpm's from the computer, just no guage). Additionally, the TCS light is on and TCS will not engage.

So, three new problems, no tach, hard shifting between gears (while driving too), and no TCS.

They checked all the fuses and replaced some kind of sensor inside the trans (removed the pan and the sensor is right there, not sure what it is).

I'm now being referred to another shop that does electrical work. The shop owner said he would pay for anything that they may have done to cause this, but I wanted to post here to see if anybody had experienced this before.

Any ideas?

Thanks,

Bob

**2001NBMZ28** · 05-25-2007, 03:39 PM

Man I don't have a clue. Is it throwing any codes? Hard shifts could mean the trans is in "limp mode." Did they replace the fuel pump/remove the rear?

**Bob Savage** · 05-25-2007, 03:46 PM

Originally Posted by 2001NBMZ28

Man I don't have a clue. Is it throwing any codes? Hard shifts could mean the trans is in "limp mode." Did they replace the fuel pump/remove the rear?

Yes, it's throwing a code. I just called them and the code is PO743 (Pressure Control Solenoid). They replaced the Pressure Control Solenoid so the shop is confident that's not really the problem.

They did replace the fuel pump. When you say "remove the rear," are you talking about the rear end? They did mention that the rear had to be dropped to do the pump, but quite frankly, I wasn't sure whether they really had to do that or it was a way of justifying the amount of money they wanted to do it.

**2001NBMZ28** · 05-25-2007, 04:33 PM

OK well that code I'm not finding - sure it's P0743? Maybe P0758 or P0753 or something else? I'd have that checked to be sure (auto zone will read it free). If they removed the rear to do the pump one of the TCS/ASR sensors at the rear wheels probably isn't plugged in all the way causing the traction control problem. Don't know why the tach is inop?

**Bob Savage** · 05-26-2007, 06:06 AM

Originally Posted by 2001NBMZ28

OK well that code I'm not finding - sure it's P0743? Maybe P0758 or P0753 or something else? I'd have that checked to be sure (auto zone will read it free). If they removed the rear to do the pump one of the TCS/ASR sensors at the rear wheels probably isn't plugged in all the way causing the traction control problem. Don't know why the tach is inop?

That's definitely the code they gave me. Maybe I'll stop at AZ and have them read it for me just to be sure.

Can you guide me to where I might find the TCS/ASR sensors you're speaking of? If they're exposed connections, I'll get under there and check it myself.

Thanks for the input!

**Bob Savage** · 05-26-2007, 06:28 AM

It's not an easy task since I have the Eibach Sportsline springs on the car, but just got under there to take a look and I see connectors on each side. They seemed like they're plugged in. Ugh...

**T/A Syco** · 05-26-2007, 08:36 AM

Just had a similar problem... Shifting all out of whack, high idle, and TCS off..... I had water in the TPS sensor on the Throttle Body... Give it a shot and check that out...

**Bob Savage** · 05-26-2007, 08:41 AM

Originally Posted by T/A Syco

Just had a similar problem... Shifting all out of whack, high idle, and TCS off..... I had water in the TPS sensor on the Throttle Body... Give it a shot and check that out...

This could make some sense since he pressure washed the engine. Where's the TPS sensor (sorry, my tech knowledge is very, very limited)?

Thanks.

**T/A Syco** · 05-26-2007, 09:05 AM

drivers side of the throttle body.... the top plug is your idle solenoid, the bottom is the tps... two screws hold her on... take it off (it's notched to go back on correctly) and tap the it in your hand... if you see some water on the inside of the sensor, let her dry up and slap it back on... Hopefully this helps you out..

**Bob Savage** · 05-26-2007, 09:51 AM

Excellent, thanks!

**Bob Savage** · 05-26-2007, 10:01 AM

Well, no water came out of it at all when I tapped it. Is only the plastic housing supposed to come out, or should the metal piece with the keyed spindle (or whatever it's called) come out too?

**TACE02** · 05-26-2007, 01:00 PM

Just curious, was it a dealership you took it to???
Seems like they did something wrong for sure.
And shifting hard after they serviced the tranny???

**Bob Savage** · 05-26-2007, 02:26 PM

Originally Posted by TACE02

Just curious, was it a dealership you took it to???
Seems like they did something wrong for sure.
And shifting hard after they serviced the tranny???

No, it wasn't a dealership and I'm kicking myself in the butt for not just bringing it to one.

**TACE02** · 05-26-2007, 02:40 PM

I hear ya, live and learn. I give ppl 1 chance and thats it. Mess up I go elsewhere. Unless of course it was a common/simple mistake and they fix it. Nothing beats a shop that stands by their work.

**T/A Syco** · 05-26-2007, 02:51 PM

Originally Posted by Bob Savage

Well, no water came out of it at all when I tapped it. Is only the plastic housing supposed to come out, or should the metal piece with the keyed spindle (or whatever it's called) come out too?

nope... Just the plastic piece is the sensor... Any luck after putting her back on ??

**Bob Savage** · 05-26-2007, 03:17 PM

Originally Posted by T/A Syco

nope... Just the plastic piece is the sensor... Any luck after putting her back on ??

Unfortunately, all is still the same.

**newtechnova** · 05-26-2007, 05:32 PM

bob
the pressure control soleniod is a device that controls transmission line pressure and is pulse width modulated (turned on and off) by the pcm. when the pcs looses power it defaults to full line pressure=very hard shifts. the same fuse(eng ctrl-under hood fuse box 2)that powers the pcs also controls the shift solenoids you didn't say if the trans still shifted through the forword gears if the trans looses power it will only have third gear

**Bob Savage** · 05-26-2007, 05:44 PM

Originally Posted by newtechnova

bob
the pressure control soleniod is a device that controls transmission line pressure and is pulse width modulated (turned on and off) by the pcm. when the pcs looses power it defaults to full line pressure=very hard shifts. the same fuse(eng ctrl-under hood fuse box 2)that powers the pcs also controls the shift solenoids you didn't say if the trans still shifted through the forword gears if the trans looses power it will only have third gear

Hey NTN (I had a 69 SS Nova when I was still in my teens),

The trans does shift through all the gears. First is VERY hard, second is hard but less than first, and of course the next two shifts are fairly smooth, though I figure that's because the car is moving and absorbs some of the shift shock. It's reminding me of the transmissions some of my friends had back in the early 80's. I'm getting a wicked chirp into second if I get on the gas a little.

**newtechnova** · 05-26-2007, 06:31 PM

bob
that fact that your tranny shifts means that it it getting battry voltage its possible that the repair shop knocked the connector off the pressure control solenoid when they removed or installed the trans pan

**Bob Savage** · 05-26-2007, 07:43 PM

Originally Posted by newtechnova

bob
that fact that your tranny shifts means that it it getting battry voltage its possible that the repair shop knocked the connector off the pressure control solenoid when they removed or installed the trans pan

Is the pressure control solenoid on the inside of the trans?