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.
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HOMESERVICE MANUALSPONTIAC1987FIREBIRD BASE, 2.8 S, STANDARDREPAIR AND DIAGNOSISENGINE PERFORMANCETESTING & DIAGNOSIS1987-88 COMPUTERIZED ENGINE CONTROLSCHART C8A - 200-4R TORQUE CONVERTER CLUTCH DIAGNOSIS200-4R TORQUE CONVERTER CLUTCH (TCC) DIAGNOSIS (2 OF 2)NOTES
1987 Pontiac Firebird Base, 2.8 S, Standard
200-4R Torque Converter Clutch (TCC) Diagnosis (2 Of 2): Notes
1987 Pontiac Firebird Base, 2.8 S, StandardSECTION Notes
NOTE:
Test numbers refer to test numbers on diagnostic chart.
- Unless switch or circuit No. 446 is open, the "SCAN" tester should display "NO", indicating the transmission is not in 4th gear. The 4th gear switch should only be open while in 4th gear.
- This test determines if the ECM and wiring are okay. Grounding circuit No. 446 should cause the "SCAN" to display "NO", indicating the transmission is not in 4th gear.
- Checks operation of the 4th gear switch. When the transmission shifts into 4th gear the switch should open and the "SCAN" should display "YES".
- Disconnecting the TCC connector simulates an open switch to determine if circuit No. 446 is shorted to ground or the problem is in the transmission.
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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.