1997 Saturn SL1 Engine shutting off while driving

Tiny
LELIOPHELIA
  • MEMBER
  • 1997 SATURN SL1
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 108,000 MILES
According to a code reader, this is what is wrong with my car right now.

TPS/Pedal Position Sensor A Circuit low input
Vehicle Speed Sensor Malfunction
Output Speed Sensor Circut
Gear 1 ratio incorrect

The "check engine" light has been going on randomly seldomly over the last 6 months or so, but only a couple months ago the speedometer would stop working whenever the light was on, and I could feel the engine shift gears when it happened.

But here's the real concerning problem:

I don't know if it's related, but over the last few days, my engine has shut off with no warning while driving, including once on the freeway. There aren't any noises or stutters or anything. The engine starts back up a minute or two later with no problems.
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Tuesday, January 5th, 2010 AT 5:35 PM

3 Replies

Tiny
SERVICE WRITER
  • EXPERT
Give me the code Numbers. POxxx

Automatic or manual transmission?
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Saturday, January 9th, 2010 AT 10:43 AM
Tiny
LELIOPHELIA
  • MEMBER
Automatic, and the codes are:

P0122
P0500
P0722
P0731
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Sunday, January 10th, 2010 AT 5:57 PM
Tiny
SERVICE WRITER
  • EXPERT
The stalling may or may not be related to the codes.
So clear the codes and keep an eye for which ones comes back.

For the po122:
DTC P0122 or P1122 will set if TP sensor voltage less than 0.2 volts:
Engine is running.
No other TP sensor DTCs have been set.

The throttle position (TP) sensor is a variable resistor that is connected to a five volt reference source, a ground, and an input signal at the PCM. When the throttle blade is closed, the sensor input voltage will be low and increase as the throttle is opened. The TP sensor is mounted on the throttle body and connected to the throttle shaft which is controlled by accelerator movement.
Normal voltage readings should vary smoothly from 0.4 volts to 4.7 volts 0.2 volts as the throttle is moved from closed to wide open position

The tps can be checked with a dvom.
What I would do first though is to check for any binding in the throttle bore when it is cold. Thjere should be no binding. If it stakcs at first when you manually open the throttle plate with your hand where the cable wraps around the arm at the throttle body, then it needs to be cleaned. Open the bore up and get a good look. If there is any carbon, it needs to be cleaned.

I think the PO 500, po722 and po731 are related to each other. Sounds like a speed sensor is dropping out. At least lets hope it is the sensor.

Based on the symptoms and these 3 codes, I would replace that sensor. The po731 will set if no speed is registered. There is a note in the toubletree that says to check the VSS first if there are speedo issues Like you are having.
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Monday, January 11th, 2010 AT 7:24 AM

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