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.
1993 Pontiac Firebird Formula, AutomaticFACTORY OEM SERVICE PROCEDURE
Engine Controls - Tests W/Codes - 5.7L
- Introduction
- Self-Diagnostic System
- ECM/Pcm Code Charts
- Notes
- Code 13 - Open Oxygen Sensor Circuit
- Code 14 - Coolant Temperature Sensor (Signal Voltage Low)
- Code 15 - Coolant Temperature Sensor (Signal Voltage High)
- Code 16 - OPTI-Spark Ignition System - Low Resolution Pulse
- Code 21 - Throttle Position Sensor (Signal Voltage High)
- Code 22 - Throttle Position Sensor (Signal Voltage Low)
- Code 23 - Mat Sensor (Signal Voltage High)
- Code 24 - Vehicle Speed Sensor (5.7L "F" Body)
- Code 25 - Mat Sensor (Signal Voltage Low)
- Code 26 - Quad-Driver No. 1 Error
- Code 27 - Quad-Driver No. 2 Error (5.7L "F" Body)
- Code 28 - Quad-Driver No. 3 Error (5.7L "F" Body)
- Code 32 - EGR System Error (5.7L "F" Body)
- Code 33 - Map Sensor (Signal Voltage High)
- Code 34 - Map Sensor (Signal Voltage Low)
- Code 35 - IAC Idle Speed Error Without Tech 1
- Code 35 - IAC Idle Speed Error Using Tech I
- Code 36 - OPTI-Spark Ignition System (High Resolution Pulse)
- Code 41 - OPTI-Spark Ignition System (Open Or Shorted Est)
- Code 42 - Est Circuit Grounded (5.7L "F" Body)
- Code 43 - ESC Error (W/O ESC Module) (5.7L "F" Body)
- Code 44 - Lean Exhaust Indication
- Code 45 - Rich Exhaust Indication
- Code 46 - Pass-Key Circuit (5.7L "F" Body)
- Code 51 - Faulty Prom/Mem-Cal
- Code 52 - Faulty Cal-PAK
- Code 53 - System OVERVOLTAGE (5.7L "F" Body)
- Code 55 - Fuel Lean Monitor (5.7L "F" Body)
- Code 61 - A/C System Performance (5.7L "F" Body)
- Code 63 - Right Oxygen Sensor Open
- Code 64 - Right Oxygen Sensor Lean
- Code 65 - Right Oxygen Sensor Rich
- Code 66 - A/C Pressure Sensor
- Code 67 - A/C Pressure Sensor (5.7L (VIN P) "F" Body)
- Code 68 - A/C Relay Circuit Shorted
- Code 69 - A/C Compressor Relay
- Code 71 - A/C Temperature (Circuit Open Or Shorted)
- Code 85 - Prom Error & Code 87 - EEPROM Error
- Summary
Factory Service Tools
Use the Manual With the Right Hardware
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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.