Circuit Description The engine coolant temperature (ECT) sensor is a thermistor that controls signal voltage to the PCM. When the engine is cold, the sensor resistance is high, therefore the PCM will see high signal voltage. As the engine warms, sensor resistance becomes less and voltage drops. The voltage measured across the thermistor is interpreted… Read More »
Circuit Description The engine coolant temperature (ECT) sensor is a thermistor that controls signal voltage to the PCM. When the engine is cold, the sensor resistance is high, therefore the PCM will see high signal voltage. As the engine warms, sensor resistance becomes less and voltage drops. The voltage measured across the thermistor is interpreted… Read More »
Circuit Description The intake air temperature (IAT) sensor is a thermistor that controls signal voltage to the PCM. When the air is cold, the sensor resistance is high, therefore the PCM will see a high signal voltage. As air warms, sensor resistance becomes less and voltage drops. Conditions for Running the DTC • The PCM… Read More »
C ircuit Description The intake air temperature (IAT) sensor is a thermistor that controls signal voltage to the PCM. When the air is cold, the sensor resistance is high, therefore the PCM will see a high signal voltage. As air warms, sensor resistance becomes less and voltage drops. Conditions fo r Running the DTC •… Read More »
Circuit Description The mass air flow (MAF) sensor measures the amount of air entering the engine during a given time. The PCM uses the mass air flow information to monitor EGR flow rates. A large quantity of air entering the engine indicates an acceleration or high load situation, while a small quantity of air indicates… Read More »
Circuit Description The mass air flow (MAF) sensor measures the amount of air entering the engine during a given time. The PCM uses the mass air flow information to monitor EGR flow rates. A large quantity of air entering the engine indicates an acceleration or high load situation, while a small quantity of air indicates… Read More »
Refer to Fuel Pump Controls Circuit Description When the key is turned ON, the PCM energizes the fuel pump relay which sends voltage to the lift pump. The lift pump remains ON during the glow plug cycle. If the engine is not started immediately after the glow plug cycle, the PCM shuts the fuel lift… Read More »
Circuit Description This chart assumes that battery condition and engine cranking speed is OK. The quantity and quality of fuel is OK and the glow plug system is operating properly. Diagnostic Aids If no trouble is found and the cause of an Engine Cranks But Will Not Run has not been found, check for the… Read More »
Refer to Power, Ground, MIL and DLC. Circuit Description There should always be a malfunction indicator lamp (MIL) when the ignition is ON and the engine is OFF. Battery ignition voltage is supplied to the lamp. The PCM will ti ‘rn the lamp ON by grounding the ignition feed circuit. Test Description Number(s) below refer… Read More »