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 MANUALSCHEVROLET1990CAPRICE BROUGHAM LS, 5.0 EREPAIR AND DIAGNOSISENGINE PERFORMANCESYSTEMENGINE CONTROLS - TESTS W/CODES - CARBURETED
1990 Chevrolet Caprice Brougham LS, 5.0 E
Engine Controls - Tests W/Codes - CARBURETED
1990 Chevrolet Caprice Brougham LS, 5.0 ESECTION Engine Controls - Tests W/Codes - CARBURETED
- Introduction
- Self-Diagnostic System
- Diagnostic Tests
- Diagnostic Circuit Check
- System Performance Check
- Chart A-1, Dwell Fixed Less Than 10 Degrees
- Chart A-2, Dwell Fixed Between 10°-50°
- Chart A-3, Dwell Fixed Greater Than 50 Degrees
- Chart A-5, No "Service Engine Soon" Light
- Chart A-6, "SES" Light On, Won't Flash Code 12
- Chart B-1, Restricted Exhaust System Check
- Code 12, No Distributor Reference Pulses
- Code 13, Open Oxygen Sensor Circuit
- Code 14, Coolant Temp Sensor Signal Voltage Low
- Code 15, Coolant Temp Sensor Signal Voltage High
- Code 21, TPS Signal Voltage High
- Code 22, TPS Signal Voltage Low
- Code 23, M/C Solenoid Signal Voltage Low
- Code 24, Vehicle Speed Sensor
- Code 31, Canister Purge Solenoid Volt Signal Incorrect
- Code 34, Pressure Sensor Signal Voltage Incorrect
- Code 41, No Distributor Reference Signal
- Code 42, Electronic Spark Timing
- Code 43, Electronic Spark Control Signal Voltage Low
- Code 44, Lean Exhaust Indication
- Code 45, Rich Exhaust Indication
- Code 51, Prom
- Code 53, EGR System Malfunction (CALIF Only)
- Code 54, M/C Solenoid Signal Voltage High
- Chart C-1D, Pressure Sensor
- Chart C-2C, Idle Load COMPENSATOR
- Chart C-2D, Rear Vacuum Break
- Chart C-2F, TPS Enrichment Check
- Chart C-3, Canister Purge Solenoid
- Chart C-4A, Ignition System Check
- Chart C-4K, Electronic Spark Timing Performance Check
- Chart C-5, Electronic Spark Control
- Chart C-6A, Air Management Check
- Chart C-7C, EGR Check
- Chart C-8, Torque Converter Clutch Elect Diagnosis
- Chart C-9C, Vacuum Actuated EFE System Check (Non-CEC)
- Chart C-10C, A/C Cut-Out Relay
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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.