Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
SYS.OK|MANUAL.DB● LIVE
HOMESERVICE MANUALSOLDSMOBILE1998ACHIEVA 3.1 M, 4T40E/MN4REPAIR AND DIAGNOSISENGINE PERFORMANCETESTING & DIAGNOSISENGINE CONTROLS - TESTS W/CODES - 3.1LSELF-DIAGNOSTIC SYSTEMDLC DIAGNOSIS OR NO SCAN TOOL DATA
1998 Oldsmobile Achieva 3.1 M, 4T40E/MN4
DLC Diagnosis Or No Scan Tool Data
1998 Oldsmobile Achieva 3.1 M, 4T40E/MN4SECTION DLC Diagnosis Or No Scan Tool Data
- Perform POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK , then go to next step.
- Turn ignition on with engine off. Connect a test light between DLC battery feed circuit and ground circuit. See WIRING DIAGRAMS - 3.1L article. If test light illuminates, go to step 4). If test light does not illuminate, go to next step.
- Using a test light connected to ground, probe DLC battery feed circuit. See WIRING DIAGRAMS - 3.1L article. If test light illuminates, go to step 9). If test light does not illuminate, go to step 10).
- Turn ignition on with engine off. Using DVOM connected to ground, probe DLC class 2 serial data circuit. See WIRING DIAGRAMS - 3.1L article. DVOM should read zero volts. If voltage is as specified, go to next step. If voltage is not as specified, go to step 7).
- Turn ignition off. Disconnect PCM connector. Turn ignition on with engine off. Using DVOM connected to battery voltage, probe DLC class 2 serial data circuit. See WIRING DIAGRAMS - 3.1L article. DVOM should read zero volts. If voltage is as specified, go to next step. If voltage is not as specified, go to step 8).
- Check for open in class 2 serial data circuit between DLC and PCM. Repair as necessary. After repairs, perform POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK . If circuit is okay, go to step 11).
- Check for short to voltage in class 2 serial data circuit. Repair as necessary. After repairs, perform POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK . If circuit is okay, go to step 11).
- Locate and repair short to ground in class 2 serial data circuit. After repairs, perform POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK .
- Locate and repair open in DLC ground circuits. After repairs, perform POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK .
- Locate and repair open or short to ground in DLC battery feed circuit. After repairs, perform POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK .
- Replace PCM. Perform PCM relearn procedures. After repairs, perform POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK .
RENDER: 1.0x
NO RELATED
Recommended Tools & Savings
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
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.