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 MANUALSCHEVROLET1995BLAZER 4D UTILITY, AWDREPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCETESTING & DIAGNOSISENGINE CONTROLS - TESTS W/CODES - 4.3LTROUBLE CODE CHARTSCODE P0123, THROTTLE POSITION SENSOR SIGNAL HIGH "S" & "T" SERIES 4.3L (VIN W)DIAGNOSTIC AIDS

1995 Chevrolet Blazer 4D Utility, AWD

Diagnostic Aids

1995 Chevrolet Blazer 4D Utility, AWDSECTION Diagnostic Aids

Tech 1 displays throttle position in volts. With closed throttle, ignition on, or at idle, voltage should be .45-.85 volt. If voltage is not as specified, replace TP sensor. Check for:

Poor Connection Or Damaged Harness

Inspect control module harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wire connection, and damaged harness.

Intermittent Test

Monitor TP sensor voltage display on Tech 1 while moving related connectors and wiring harness. If failure is induced, display will change. This may assist in isolating location of malfunction.

TP Sensor Scaling

Observe TP sensor voltage display while depressing accelerator pedal with engine stopped and ignition on. Display should vary from closed throttle TP sensor voltage when throttle is closed (less than 1.25 volts) to greater than 4.5 volts when throttle is held at WOT position.

Fig 1: Code P0123 Schematic (4.3L "S" & "T" Series - VIN W) Throttle Position Sensor Signal High

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.