Code P0719 and ABS light on

rsrxc700 · May 12, 2005

1997 Z-71 w/ 5.7L. Wondering if anyone could help me get started in troubleshooting this.

Have P0719 (Tourque Conv/Brake Switch B Circut Low)

I also have P01406 (EGR Position) and will try to clean before I replace it. Could the other code be related to this?

The ABS light is also on.

Any advise would be helpfull on where to start.

Thanks!

RSR

GM-Tech · May 12, 2005

The TCC part of the brake switch is normally closed. That is, 12 volts is going through it to the PCM until you step on the brake. If the PCM doesn't see 12 volts at that pin when you're accelerating (obviously not braking) then it sets that DTC.

Since you also have an ABS light on, you may just have a bad brake switch.

The EGR code is unrelated to either of those.

rsrxc700 · May 12, 2005

The TCC part of the brake switch is normally closed. That is, 12 volts is going through it to the PCM until you step on the brake. If the PCM doesn't see 12 volts at that pin when you're accelerating (obviously not braking) then it sets that DTC.

Since you also have an ABS light on, you may just have a bad brake switch.

The EGR code is unrelated to either of those.

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Thanks!

Are you talking about the brake switch by the brake pedal?

Do you recall how do you remove it? It is a little tight in there.

Thanks again!

RSR

GM-Tech · May 13, 2005

Are you talking about the brake switch by the brake pedal?

Yes.

Replacing it isn't too bad. Getting the retaining clip off is the worst! Be sure you get a new clip because there will be nothing left to put back on when you go to reinstall everything. Remove the clip and unsnap the switch from the pushrod. Then it just slips off.

Martin001 · May 20, 2005

I have the same problem, although it started with only the ABS light staying on after start, and that disabled the fan, AC, and cruise control. I found a circuit that served the ABS and the other systems I mentioned, removed the 60 amp fuse on the driver's side wheel well, tightened the contact tabs, replaced the fuse, and that worked... until now. The check engine and ABS light came on and it threw the same code mentioned in the previous email. WOuld that still be the brake switch?

GM-Tech · May 20, 2005

What kind of vehicle are we talking about? We have had problems with ignition switches in Trailblazers and it would cause the ABS/Brake light to be on, A/C inoperative, etc., etc.

Martin001 · May 20, 2005

What kind of vehicle are we talking about? We have had problems with ignition switches in Trailblazers and it would cause the ABS/Brake light to be on, A/C inoperative, etc., etc.

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Martin001 · May 20, 2005

What kind of vehicle are we talking about? We have had problems with ignition switches in Trailblazers and it would cause the ABS/Brake light to be on, A/C inoperative, etc., etc.

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I have a 1997 GMC K1500 Extra-cab 4WD Z71 with a 350ci (5.7L) V8, Auto trans

Martin001 · June 8, 2005

Dear GM-Tech,

I was hoping to hear more after supplying my vehicle description. Can you help me repair this problem? Thanks.

What kind of vehicle are we talking about? We have had problems with ignition switches in Trailblazers and it would cause the ABS/Brake light to be on, A/C inoperative, etc., etc.

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I have a 1997 GMC K1500 Extra-cab 4WD Z71 with a 350ci (5.7L) V8, Auto trans

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GM-Tech · June 9, 2005

Can you help me repair this problem?

Not without some more specific diagnostic info.

Martin001 · June 19, 2005

Can you help me repair this problem?

Not without some more specific diagnostic info.

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What other diag. info do you need?

GM-Tech · June 19, 2005

What other diag. info do you need?

Do you have power to the brake switch for the TCC circuit? That's not the stop lamp circuit of the switch. I think the wire colors are brown and purple. You should have power at both wires when you're not stepping on the brake and power to the purple wire should go away when you step on the brake.

If that checks out, you need to find out if that power is making it to the VCM. I don't have schematics for a 1997 handy, so I can't tell you what pin you'd need to check.