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1999 Saturn SL-2

Tiny
NJDEATHBLOOMS
  • MEMBER
  • 1999 SATURN
Ok, i've been having a problem for a while with my 1999 saturn SL-2 automatic transmission. My car occasionally will not start, but the starter is good. The starter is making contact, not clicking or grinding, but the car just won't start. Also, at random points when I am driving, the car acts like its in neutral. It will start slowing down, coast to a stop, and die. If I put my foot down all the way on the gas pedal, it won't even rev. My service engine light indicated "Throttle Positioning Sensor". I replaced that today, and it's still doing the same thing. I've also cleaned the EGR valve, and it's not helping either. Two questions: Is there something called an EGR flow sensor, and if so, could this be the problem? And if not, what is my next step? Update: I took it back to auto zone as my service engine light is back on AGAIN. Tested battery alternator and starter. All passed. When they hooked the diagnostic thing up to check for codes. It kept saying "error communicating with vehicle."
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Thursday, April 26th, 2007 AT 9:32 AM

13 Replies

Tiny
PEPPERMRJ
  • MECHANIC
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Hey njdeathblooms,

The first thing I want you to do is the next time the car won't start or dies. Remove the spark plug wires from the coils. Have someone crank the starter while you watch for spark between the coil towers. Be sure to mark the wires so they can be reinstalled properly.

Does the car just die when it is running or does it idle till you come to a stop and then die?

Just for the heck of it check all fuses. Both the underhood box and the one in the passenger compartment. Use a test light or an ohm meter. Looks can sometimes be deceiving.

No EGR flow sensor to my knowledge. Try another place to read the codes. Hopefully it is their code reader. Having the specific trouble code numbers would be a big help. Never heard of the computer coming loose from it's wiring. Has there been any water damage?

Good luck and let us know. :)
peppermrj
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Friday, April 27th, 2007 AT 4:47 PM
Tiny
NJDEATHBLOOMS
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Ok well, the car hasn't given me any problems today. Yet. I replaced the PCV valve today, and took some carb/choke cleaner and re-cleaned the EGR valve and the throttle body. If it won't start/dies again soon i'll let you know about the spark issue. All fuses & relays under the hood are ok, all fuses & relays in passenger compartment are good, except the cig lighter. Lol. I think the guys at autozone had a bad diagnostic machine. I took it back today, and the codes were P0401 (Egr flow insufficient), that's why I cleaned the EGR valve. I also disconnected the battery cables to check for corrosion. The other code was P1635, and it said something about Manufacturer Auxilliary Input/output I think. To answer your other question, when i'm driving, if it's going to die the car idles at about 2000 RPMs until I come to a stop and THEN it dies. It will also idle just below 1,000 RPMs if i'm just sitting at a traffic light or stop sign. Close to maybe 750 RPMs. And there's been no water damage that I know of. Not since i've owned it.
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Friday, April 27th, 2007 AT 5:57 PM
Tiny
PEPPERMRJ
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DTC P1635

The 5 volt reference circuit provides a signal voltage to the linear EGR, MAP sensor, and TP sensor. The return line is grounded through the PCM. DTC P1635 detects a short to ground in any of the 3, 5 volt reference circuits or inside the PCM.

Conditions for Setting the DTC

Important
The 5 volt reference is monitored whenever the ignition is ON.

DTC P1635 will set if the 5 volt reference signal is below 3.5 volts or above 5.5 volts. This voltage is monitored internally by the PCM.

Diagnostic Aids
If DTCs P0563, P0108, P1106, P0452, P0453, P1122, or P0122 are set, a short to battery voltage (12) on the 5 volt reference circuit is probable. If the short exists while attempting to diagnose trouble codes, PDT communications will be lost and driveability conditions will exist.

Ok so much for the technical info. The PCM sends out 5 volts to the thottle position sensor, the egr valve, and to the map sensor. The amount of voltage returned to the pcm is determined by the function of these various item. That is how the computer reads there function, by the return of anywhere from 0 to 5 volts. Any one of these itrems being faulty can set this code. A short to ground or to power can set this code. A faulty computer can set this code.

There is a diagnostic procedure for this code that involves probing terminals on the computer with a test light. Let me know if you wish to attempt it and I will send it to you.

Being that you have codes for both the egr and the throttle position sensor (do you remember whcih one exactly) I am leaning towards a short of some type. The PCMs are pretty solid on these cars unless they have been shorted out.

The cabin fuse box on my 96 is under the dash to the left of the steering column. Check your owners manual for yours. Check the fuses again especially the PCM fuse. Test it with a light or meter. Make sure it is clean and tight and its receptical is also.

I need to correct an earlier statement I made. There is an EGR flow sensor. It is an intregal part of the EGR valve.

Good hunting and let us know. :)
peppermrj
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Friday, April 27th, 2007 AT 8:43 PM
Tiny
NJDEATHBLOOMS
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Ok I checked all the fuses again (using a combination fuse puller/tester), all are good. I don't know if I know enough about cars to try to probe the PCM terminals & check for a short (like.I didn't really understand anything you said about volts and circuits and the like) but if you have procedures for it, i'll definitely try my best. Also, I keep looking for something with the little aluminum fins on it, but cant find it. Where would I find the PCM computer? Is it under the hood or like under the dashboard? I don't know where to look. Told you I was car illiterate.
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Friday, April 27th, 2007 AT 11:43 PM
Tiny
NJDEATHBLOOMS
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I've checked the reference voltage to the TPS, EGR valve and MAP sensor. All of them showed 5.02 volts. In addition, I checked the resistance in each circuit with an ohmmeter, and it was within the range my repair manual said it should be. My spark plugs are good, I also checked for spark between the coil towers like you asked me to a while ago, and I have spark. What is my next step? Do I need to probe the PCM terminals now? Thanks again for all your help.
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Friday, May 4th, 2007 AT 12:50 PM
Tiny
PEPPERMRJ
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Hey NJ,

The PCM is located under the left side of the dash. PITA! The later models have them next to the battery.

Be careful when dealing with the PCM. It only takes 30 volts of static electricity to fry the PCM. It takes about 1200 volts of static electricity to make a spark if I remember correctly. Be sure to ground yourself before touching the PCM. Also be sure the battery is disconnected and the ignition is off.

Where any of the trouble codes mentioned under "Diagmnostic Aids" in my prior post ever present? Please Double check!

Check your PMs for the procedure. Be forwarned that if a short exists and is not corrected you can fry a replacement PCM. I would try a used one from a recycler myself if needed.

Good luck and let us know. :)
peppermrj
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Saturday, May 5th, 2007 AT 3:30 PM
Tiny
PEPPERMRJ
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https://www.2carpros.com/forum/automotive_pictures/4270_99_saturn_pcm_location_1.jpg

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Saturday, May 5th, 2007 AT 3:32 PM
Tiny
NJDEATHBLOOMS
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Okay, i've located what is unquestionably the PCM. But I don't know which harness to disconnect. They don't seem to be labeled, and my repair manual is zero help. Lol. And no, none of those codes were mentioned, just P1635.
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Sunday, May 6th, 2007 AT 10:35 PM
Tiny
NJDEATHBLOOMS
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Ok, i'm waiting on a day off from work to mess with the PCM, so in the meantime, if it helps, I went and bought an OBD2 code reader. It's an INNOVA CanOBD2 3100a. The useful thing about it is that it can transfer data to my PC. Here is the report I got from it. This all took place with the ignition ON but not running.

Report#: 1
Report Date: 5-8-2007 (3:55 AM)
Vehicle Year: 1999
Vehicle Make: Saturn
Vehicle Model: SL2
Vehicle Engine Size:
Vehicle VIN:
Vehicle License Plate: DTE 8073
Vehicle Mileage: 124000

Stored:
P0401 Exhaust Gas Recirculation Flow Insufficient Detected
P0401 Exhaust Gas Recirculation Flow Insufficient Detected
P1635 Five Volt Reference Error Circuits High Or Low (1997-2000)
[NOTE: THAT IS WHAT THE BOOK SAYS. THE READER SAYS P1635GM IGNITION 1 POWER CIRCUIT VOLTAGE LOW]
P0122 Throttle/Pedal Position Sensor A Circuit Low Input

MIL ON
MisFire Monitor Complete
Fuel System Monitor Complete
Comprehensive Component Monitor Complete
Catalyst Monitor Not Complete
Heated Catalyst Monitor Not Supported
Evaporative System Monitor Not Complete
Secondary Air System Monitor Not Supported
A/C System Refrigerant Monitor Not Supported
Oxygen Sensor Monitor Complete
Oxygen Sensor Heater Monitor Complete
EGR System Monitor Complete

DTC for which Freeze Frame was Stored P1635
Fuel System 1 Status Closed Loop
Fuel System 2 Status Not Supported
Calculated LOAD Value 3.92 %
Engine Coolant Temp 168.80 °F
Short Term Fuel Trim - Bank 1 0.00 %
Long Term Fuel Trim - Bank 1 -5.47 %
Intake Manifold Absolute Pressure 2.95 inHg
Engine RPM 3113 rpm
Vehicle Speed Sensor 77.05 mph
Absolute Throttle Position 0.00 %

Automatic Transmission Problems:
No Symptoms
Check Engine Light:
Light Always On
Driving Conditions When Problem Occurs:
Less Than 2 Miles
2-10 Miles
More Than 10 Miles
With Headlights On
Always
Driving Habits:
Mostly City Driving
Park Vehicle Outside
Drive Less Than 10 Miles Per Day
Engine Quits Or Stalls:
Right After Starting
When Shifting Into Gear
While Idling
During Acceleration
Engine Temperature When Problem Noticed:
Cold
Warm
Problem First Noticed:
Started Last Month
Gasoline Used:
87 Octane
Idling Conditions:
Sometimes Too Fast Or Too Slow
Is Rough Or Uneven
Fluctuates Up And Down
Peculiar Smells:
No Symptoms
Problem Occurs:
Morning
Afternoon
Problems Starting Vehicle:
Cranks, but Will Not Start
Running Conditions:
Runs Rough
Strange Noises:
Weather Conditions When Problem Occurs:
32-55 F (0-13 C)
Above 55F (13C)
Transmission Type:
Automatic
Describe The Problem:
Engine stalls at random points while driving. Engine will die at stop lights, or idle until
i come to a stop and then die. Engine is also difficult to restart immediately afterwards.
Previous Repairs:
Throttle Position Sensor installed, Installed new starter, new EGR valve, new MAP sensor.
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Tuesday, May 8th, 2007 AT 3:06 AM
Tiny
PEPPERMRJ
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Hey Nj,

Before you do anything else clear the codes using the scanner and see what returns. It will take a few drive cycles before everything is tested again so give it some time.

I do believe that one of the codes mentioned in "diagnostic aids" is for the throttle position sensor code you have had previously. Yes no?

No sense trying to fix a prob that already has been.

Peppermrj
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Tuesday, May 8th, 2007 AT 2:12 PM
Tiny
NJDEATHBLOOMS
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Yes, the P0122 code is there.I erased the codes, and the P0122 (Throttle/pedal position sensor circuit A low input) didn't come back. Yet. I have 2 P1635s (Five volt ref circuit) and 2 P0401s (EGR flow insufficient).
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Tuesday, May 8th, 2007 AT 10:43 PM
Tiny
NJDEATHBLOOMS
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Ok. The P0122 is now back. Lol.
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Wednesday, May 9th, 2007 AT 10:06 PM
Tiny
NJDEATHBLOOMS
  • MEMBER
  • 10 POSTS
Report Date: 5-11-2007 (11:29 PM)
Last Name:
First Name:
Address:

Phone Number:
Email:
Vehicle Year: 1999
Vehicle Make: Saturn
Vehicle Model: SL2
Vehicle Engine Size:
Vehicle VIN:
Vehicle License Plate: DTE 8073
Vehicle Mileage: 124000

Stored:
P0108 Manifold Absolute Pressure/BARO Sensor High Input
P0122 Throttle/Pedal Position Sensor A Circuit Low Input
P0401 Exhaust Gas Recirculation Flow Insufficient Detected
P0405 Exhaust Gas Recirculation Sensor A Circuit Low
P1635 1. Five Volt Reference Error (1996)
2. Five Volt Reference Error Circuits High Or Low (1997-2000)
P0452 Evaporative Emission System Pressure Sensor/Switch Low Input

Pending:
P0401 Exhaust Gas Recirculation Flow Insufficient Detected

MIL ON
MisFire Monitor Complete
Fuel System Monitor Complete
Comprehensive Component Monitor Complete
Catalyst Monitor Not Complete
Heated Catalyst Monitor Not Supported
Evaporative System Monitor Complete
Secondary Air System Monitor Not Supported
A/C System Refrigerant Monitor Not Supported
Oxygen Sensor Monitor Not Complete
Oxygen Sensor Heater Monitor Complete
EGR System Monitor Complete

DTC for which Freeze Frame was Stored P0401
Fuel System 1 Status Closed Loop
Fuel System 2 Status Not Supported
Calculated LOAD Value 14.12 %
Engine Coolant Temp 170.60 °F
Short Term Fuel Trim - Bank 1 6.25 %
Long Term Fuel Trim - Bank 1 -10.94 %
Intake Manifold Absolute Pressure 6.50 inHg
Engine RPM 1875 rpm
Vehicle Speed Sensor 47.23 mph
Absolute Throttle Position 0.00 %

ok here are all the codes that are stored now. The P0108, P0122, and P0452 are all under "Diagnostic aids" up there.
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Friday, May 11th, 2007 AT 10:38 PM

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