SES light on & surging idle

[junk]

Recently the SES light came on. And now it has a surging idle. The idle is surging bad enought the envoy is undrivable. Any suggestions regarding this?

And what is a decent OBD-2 scanner to buy? I'm thinking about buying an Equus 3100 scannet that walmart sells for $100.

Thanks
Jeremy

[deathbynosleep]

Recently the SES light came on. And now it has a surging idle. The idle is surging bad enought the envoy is undrivable. Any suggestions regarding this?

And what is a decent OBD-2 scanner to buy? I'm thinking about buying an Equus 3100 scannet that walmart sells for $100.

Thanks
Jeremy
You could buy it, use it...then return it. Is the SES light still on? Or did it just flicker?

[IceN]

just go to autozone. They will scan it for free and tell u what is wrong, and then reset the ses light for u.

[junk]

I bummed a scanner from a buddy and it came up with codes 507 & 1512. 1512 I can't find in the book, but 507 was related to idle. Does anyone have any experience with these codes?

Thanks
Jeremy

[zamar]

I bummed a scanner from a buddy and it came up with codes 507 & 1512. 1512 I can't find in the book, but 507 was related to idle. Does anyone have any experience with these codes?

Thanks
Jeremy

Welcome Jeremy

P1512 is mfg specific.

P0507

CIRCUIT DESCRIPTION
The throttle actuator control (TAC) motor is controlled by the powertrain control module (PCM). The DC motor located in the throttle body drives the throttle plate. In order to decrease idle speed, the PCM commands the throttle closed reducing air flow into the engine and the idle speed decreases. In order to increase idle speed, the PCM commands the throttle plate open allowing more air to pass the throttle plate. If the actual idle RPM does not match the desired idle RPM within a calibrated time, this DTC sets.

P1512

CIRCUIT DESCRIPTION
The commanded throttle position is compared to the actual throttle position based on accelerator pedal position and possibly other limiting factors. Both values should be within a calibrated range of each other. The powertrain control module (PCM) continuously monitors the commanded and actual throttle positions. This diagnostic trouble code (DTC) sets if the values are greater than the calibrated range.

Walmart actually sells one for $68 as well. :yes: I'd reset it and see if it comes back. Computers do funny things when it turns cold.

[tblazed]

Sounds to me like the symptom of a vacuum leak somewhere. PCM can't control idle with normal function of the throttle and setting a related code... idle surging up and down...

Or maybe a failed throttle body not responding properly to PCM commands.

[junk]

Thanks for the info. I'm going to start digging into it looking for a vacuum leak. The light has come & gone once already, so I'm assuming it is a fairly consistent problem causing the codes. I'll also check out the throttle body to make sure it looks OK.

The Envoy was wrecked pretty good when I got it, but had been doing good for about 4k miles until this.

Where did you get the manufacturer specific codes?

Also is the 68$ scanner any good? I was afraid it wouldn't be as good. My buddies is Walmarts 100$ unit.

Thanks the great info.

Thanks
Jeremy