Thread: P1629 and P1673

P1673

Description
ENGINE HOT LIGHT CONTROL CIRCUIT

Output Driver Modules (ODM) are used by PCM to turn on
current-driven devices needed to control various engine and transaxle
functions. Each ODM can control up to 7 outputs by supplying ground to
device PCM is commanding on. ODMs can diagnose each circuit
individually. If ODM output (ENGINE HOT light indicator driver
circuit) detects an improper voltage level, DTC will set.

Symptoms
You likely won't notice any drivability problems.

Causes

An improper voltage level has been detected on ENGINE HOT
light indicator driver circuit.

Solutions

Check for shorts or bad connections in ENGINE HOT light
control circuit.
Replace fuse.


P1629

Description
THEFT DETERRENT CRANK SIGNAL MALFUNCTION

Vehicle operation is disabled if incorrect key or starting
procedure is used. Vehicle Theft Deterrent (VTD) module enables crank
circuit to starter and sends a signal to PCM if correct key is being
used. If proper signal does not reach PCM fuel enable signal circuit,
PCM will not pulse injectors on, disabling vehicle, even if crank
circuit is by-passed. Signal should be between 40-60 Hz and is
measured using DC scale on DVOM.

Symptoms
Engine will not run

Causes

PCM detects incorrect signal on theft deterrent fuel enable
circuit.

Solutions

Check for faulty connection at TDS module.
Bypass VATs(92-99 only)
Replace VTD module.


Are these codes any thing I should worry about. They came up on my aeroforce the other Day I cleared them and they have not come back on. Now I have had a few really cold days where I have used my Remote start and then when I get in the car and put the key in to drive away the Security light stayed on till I shut the car off and used the key to start it. Now I have started my car many times witht the remote start and only twice has the Security light stayed on.

And what is the ENGINE HOT LIGHT CONTROL CIRCUIT

any one have any info on these??

You posted the info about them. When was the last time the car started then stalled?

Originally Posted by fomas

So how do you fix the p1673 code need help I have this code 99 grand prix gt

When you cycle the key, does the "Engine Hot" or "Overheat" (or whatever the warning light for over temp says) light up during the bulb check?

It sounds like an issue with the after-market remote start. These need to override anti-theft systems since the security chip in the key won't be present when you start the car remotely. I'd be checking the remote start unit. It may be failing or may have a loose connection.

Originally Posted by fomas

No everything seems fine runs at the right temp 180 thermostat installed.
there is no over heat warning light just the gauge.

I think we're talking past each other. I just did some reading on the Google. *IF* I'm understanding the code set criteria correctly, the code has nothing to do with the actual engine temperature.

It is there to warn you that your "Idiot light" in the instrument cluster is malfunctioning. I assume they have a code just for this because nobody pays attention to the actual temp gauge.

This is why I asked very specifically if the warning light illuminates during the "bulb check" when you start the car.

I dont think there is a warning light for over heating. There is a low coolant light check engine light but no over heating light. As far as I can tell they all work none
are unlimited .
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