1992 Saturn SL1 AutomaticFACTORY OEM SERVICE PROCEDURE

Ignition System

  1. Install "Scan" tester. Check for stored ECM trouble codes. Scan TPS voltage. If TPS reading is less than .2 volt or greater than 2.5 volts, use Code 21 chart first. Scan CTS temperature. If scanned coolant temperature is less than -38°C, use Code 14 chart first. See appropriate G - TESTS W/ CODES article in this section. Scan RPM on "Scan" tester while cranking engine. If no RPM is displayed, go to step 6).
  2. If all parameters scan okay, probe fuel pump test connector (Red wire located behind left front shock tower) with a test light connected to battery voltage. With ignition off, test light should be on. Turn ignition on. Test light should go out for about 2 seconds and then come back on. If test light functions as described, go to next step. If not, check fuel pump relay power supply, driver circuit and windings.
  3. Using Spark Tester (ST-125), check for spark on spark plug wires 1 and 2 or 3 and 4. Check one wire at a time, leaving other wires connected during cranking. If spark does not occur on both plug wires, go to step 6). If spark occurs on both wires, turn ignition off. Disconnect 3-wire injector harness connector. Using DVOM, measure resistance between Black/Red wire and Light Blue wire on injector side of harness. See Fig 1. Measure resistance between Black/Red wire and Light Green wire on injector side of harness. Resistance should be 5.9-6.3 ohms.
  4. If resistance is within specification during both measurements, go to next step. If resistance during either measurement is less than 5.9 ohms, repair short in harness or replace any injector which measures less than 11.8 ohms when measured individually with harness connector removed. If resistance during either measurement is greater than 6.3 ohms, repair open in harness or replace any injector which measures greater than 12.6 ohms when measured individually with harness connector removed.
  5. Reconnect 3-wire injector harness connector. Install injector test light in No. 1 injector harness connector. Crank engine. Transfer injector test light to No. 3 injector harness connector. Crank engine. If injector test light does not flash when installed in one or both injector harness connectors, go to step 10). If injector test light flashes when installed in No. 1 and 3 injector harness connectors, recheck fuel pressure. Also check for fouled spark plugs, EGR valve stuck open and a shorted A/C pressure sensor as possible causes of a no-start condition.
    CAUTION: When probing DIS circuits, ensure hands and clothing do not come into contact with rotating engine belts and pulleys.
  6. If not previously done, using Spark Tester (ST-125), check for spark on spark plug wires 1 and 2 or 3 and 4. Check one wire at a time, leaving other wires connected during cranking. If no spark is present, go to step 8). If spark occurs on one wire, turn ignition off. Check plug wire and replace if necessary. If wire is okay, disconnect 4-wire connector at ignition module.
  7. With voltmeter set on DC volts and Black lead connected to ground, probe harness terminal No. 3 and then No. 4 while cranking engine. If voltmeter reading is greater than one volt, coil module is faulty. If voltmeter does not read greater than one volt, check for open or short to ground on EST "A" and "B" circuits between ECM connector and ignition module connector. If circuits are not open or shorted to ground, problem is poor ECM connections or faulty ECM.
  8. If no spark was present in step 6), turn ignition off. Disconnect 4-wire ignition module connector. Turn ignition on. With test light connected to ground, probe 4-wire connector Pink/Black wire terminal. If test light is not on, repair open in ignition module power supply circuit. If test light is on, probe Black wire of 4-wire ignition module connector with test light connected to battery voltage. If test light is on, go to next step. If test light is not on, repair open in ignition module ground circuit.
  9. With voltmeter set on DC volts and Black lead connected to ground, probe harness terminal No. 3 and then No. 4 while cranking engine. If voltmeter reading is greater than one volt, coil module is faulty. If voltmeter does not indicate greater than one volt, check for open or short to ground on EST "A" and "B" circuits between ECM connector and ignition module connector. If circuits are not open or shorted to ground, ECM connections are poor or ECM is faulty.
  10. If light did not come on at one or both injector harness terminals, go to next step. If light was on steady on one or both injector harness terminals, turn ignition off. Disconnect ECM connectors and all injector connectors. With a test light connected to battery voltage, check injector drive circuits for short to ground. Repair as necessary. If no shorts to ground are present, problem is faulty ECM connections or faulty ECM.
  11. Turn ignition on. Remove injector test light from injector harness. Probe Black/Red wire terminal of injector No. 1 or No. 3 harness connector with a test light connected to ground. If test light is not on, repair open in injector power supply circuit. If test light is on, turn ignition off. Reconnect all injector harness connectors. Disconnect ECM connectors.
  12. Turn ignition on. Probe ECM harness connector terminals C12 and C15 with a test light connected to ground. If test light is not on at both terminals, repair open in injector drive circuits between injector harness connector and ECM harness connector. If test light is on at both ECM terminals, turn ignition off. Disconnect all 4 injector connectors. Turn ignition on. Again probe ECM connector terminals C12 and C15 with a test light connected to ground.
  13. If light is on at either terminal, repair short to voltage in that circuit. If test light is not on at either terminal, ECM connections or ECM are faulty.
Fig 1: 2.0L PFI Ignition System (Sunbird)
G92I04653Courtesy of GENERAL MOTORS CORP.
Factory Service Tools

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.

Shop Manual-Ready ToolsCompare Repair QuoteQuote Shield Pro

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

Rather have a pro handle this?

A certified mobile mechanic comes to your home or office. They bring the tools, you stay comfortable. No tow truck, no waiting room, no surprises.

Comes to youSame-day available12-month warranty
Get a Free Quote

No obligation. See pricing before you book.