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 MANUALSCHEVROLET1989SUBURBAN 1/2 TON 2WD V8-454 7.4LREPAIR AND DIAGNOSISPOWERTRAIN MANAGEMENTDIAGRAMSELECTRICAL DIAGRAMSELECTRONIC/POWERTRAIN CONTROL MODULE (ECM/PCM)
1989 Chevrolet Suburban 1/2 Ton 2WD V8-454 7.4L
Electronic/Powertrain Control Module (ECM/PCM)
1989 Chevrolet Suburban 1/2 Ton 2WD V8-454 7.4LSECTION Electronic/Powertrain Control Module (ECM/PCM)
ECM (Part 1 of 4):
A8 = SERIAL DATA.
A9 = DIAGNOSTIC TEST.
A12 = SYSTEM GROUND.
C9 = CRANK SIGNAL.
D7 = OXYGEN SENSOR SIGNAL.
D6 = OXYGEN SENSOR GROUND.
D2 = MAP GROUND (4.3L & V8 R/V,M,G,P).
A11 = MAP GROUND (4.3L & V8 C/K).
C11 = MAP SIGNAL.
C14 = +5V REFERENCE.
C13 = TPS SIGNAL.
A11 = SENSOR GROUND (4.3L & V8 R/V,M,G,P).
D2 = SENSOR GROUND (4.3L & V8 C/K).
C10 = CTS SIGNAL.
B8 = A/C SIGNAL.
ECM (Part 2 of 4):
C5 = IAC "A" HI.
C6 = IAC "A" LO.
C4 = IAC "B" HI.
C3 = IAC "B" LO.
B1 = 12 VOLT.
C16 = 12 VOLT.
A1 = FUEL PUMP RELAY DRIVE (12V).
B2 = FUEL PUMP SIGNAL.
ECM (Part 3 of 4):
A6 = SERVICE ENGINE SOON LAMP CONTROL.
C7 = HIGH GEAR SWITCH SIGNAL.
A7 = A/T TCC CONTROL GROUND.
A7 = M/T SHIFT LAMP.
A10 = VEHICLE SPEED SENSOR.
B10 = PARK NEUTRAL SWITCH (A/T)(12V)(EXCEPT P).
ECM (Part 4 of 4):
D16 = INJECTOR DRIVER.
D15 = INJECTOR DRIVER (5.7L P).
D14 = INJECTOR DRIVER.
C15 = INJECTOR DRIVER (5.7L P).
A4 = EGR SOLENOID.
A4 = EVRV SOLENOID.
C2 = EAC SOLENOID.
A6 = 12V IGNITION.
B7 = KNOCK RETARD SIGNAL (ESC) (EXCEPT P).
D4 = EST.
B6 = REFERENCE.
D5 = BYPASS.
B3 = REF. LOW.
RENDER: 1.0x
NO RELATED
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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.