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.
1990 Suzuki SamuraiFACTORY OEM SERVICE PROCEDURE
Mixture Heater System Check (Sidekick A/T)
- Check resistance of mixture heater. See MIXTURE HEATER (SIDEKICK A/T) under EARLY FUEL EVAPORATION in this article. Ensure coolant temperature is 86°F (30°C) or less. If coolant temperature is more than 86°F (30°C), disconnect coolant temperature sensor connector. Connect a resistor of approximately 10,000 ohms between harness connector terminals to simulate coolant temperature sensor resistance.
- Disconnect mixture heater 1-wire connector. Connect voltmeter between connector terminal and ground. Crank engine. If battery voltage is present, go to next step. If battery voltage is not present, check mixture heater relay and circuit. See MIXTURE HEATER RELAY (SIDEKICK A/T) under EARLY FUEL EVAPORATION in this article. If mixture heater relay is okay, go to step 5).
- Remove resistor from coolant temperature sensor connector (if connected). Connect harness connector to coolant temperature sensor. If coolant temperature is less than 86°F (30°C), warm-up engine. Turn engine off.
- With voltmeter connected between mixture heater connector terminal and ground, crank engine. If battery voltage is present, check mixture heater relay and circuit. See MIXTURE HEATER RELAY (SIDEKICK A/T) under EARLY FUEL EVAPORATION in this article. If mixture heater relay is okay, go to next step.
- Turn ignition off. Check continuity between White/Blue wire terminal of mixture heater relay and mixture heater connector. If there is continuity, go to next step. If there is no continuity, repair White/Blue wire circuit.
- Disconnect Yellow ECM connector. Turn ignition on. Check for battery voltage on ECM connector terminal A10, on harness side of connector. If battery voltage is present, go to next step. If battery voltage is not present, check White/Green wire circuit between ECM connector terminal A10 and mixture heater relay.
- Turn ignition off. Connect Yellow ECM connector. Ensure coolant temperature is less than 86°F (20°C). Crank engine. Check voltage between ECM connector terminal A10 and ground. If zero volt is present, ECM is okay. If more than zero volt is present, go to next step.
- While cranking engine, check for battery voltage between ECM connector B11 and ground. If battery voltage is present, go to next step. If battery voltage is not present, repair engine start signal circuit.
- Check coolant temperature sensor. See COOLANT (WATER) TEMPERATURE SENSOR under ENGINE SENSORS & SWITCHES in this article. Replace coolant temperature sensor if out of range or inoperative. Check ECM connectors for proper connection. If ECM connectors are okay, replace ECM.
Factory Service Tools
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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.