DTC P0100 MASS AIR FLOW CIRCUIT MALFUNCTION

Transcription

1 DIGNOSTICS DTC P0100 MSS IR FLOW CIRCUIT MLFUNCTION HI01 CIRCUIT DESCRIPTION The mass air flow meter uses a platinum hot wire. The hot wire air flow meter consists of a platinum hot wire, thermistor and a control circuit installed in a plastic housing. The hot wire air flow meter works on the principle that the hot wire and thermistor located in the intake air bypass of the housing detect any changes in the intake air temperature. The hot wire is maintained at the set temperature by controlling the current flow through the hot wire. This current flow is then measured as the output voltage of the air flow meter. The circuit is constructed so that the platinum hot wire and thermistor provide a bridge circuit, with the power transistor controlled so that the potential of and remains equal to maintain the set temperature. + Temperature Sensor Power Transistor Platinum Hot Wire Output Voltage Thermistor Platinum Hot Wire DTC No DTC Detecting Condition Trouble rea P0100 Open or short in air flow meter circuit with more than 3 sec. engine speed less than 4,000 rpm Open or short in air flow meter circuit ir flow meter ECM If the ECM detects DTC P0100 it operates the failsafe function, keeping the ignition timing and injection volume constant and making it possible to drive the vehicle. fter confirming DTC P0100, use the OD II scan tool or handheld tester to confirm the air flow ratio from CURRENT DT. Mass ir Flow Value (gm/sec.) pprox or more circuit open Malfunction Mass air flow meter power source circuit open circuit open or short 187

2 0526 DIGNOSTICS WIRING DIGRM Mass ir Flow Meter ECM From Terminal 3 of E.F.I. Relay 1 2 LW 32 E4 3 G 24 E INSPECTION PROCEDURE Read freeze frame data using handheld tester or OD II scan tool. ecause freeze frame records the engine conditions when the malfunction is detected, when troubleshooting it is useful for determining whether the vehicle was running or stopped, the engine warmed up or not, the airfuel ratio lean or rich, etc. at the time of the malfunction. 1 RED VLUE OF OD II SCN TOOL OR HNDHELD TESTER(MSS IR FLOW RTE) Read mass air flow rate on the handheld tester or OD II scan tool. Result: Mass air flow rate (gm/sec.) or more Go to step 6 2 INSPECT INTKE IR FLOW METER SUSSY(POWER SOUCE VOLTGE) Turn the ignition switch ON. Measure voltage between the terminals + and of the mass air flow meter connector. Voltage: 9 14 V +(+) () NG Go to step 5 188

3 DIGNOSTICS INSPECT ECM Turn the ignition switch ON. Measure voltage between the terminals and of the ECM connector while the engine is idling. Voltage: V The shift position should be P or N and /C switch should be turned OFF NG 4 CHECK HRNESS ND (ECMMSS IR FLOW METER) + G TH (e) (f) Disconnect the ECM E3 connector. Check continuity between the terminals of the mass air flow meter harness connector and of the Check for open between the terminals G of the mass air flow meter connector and of the Check for short between the terminals and of the Check for short between the terminals and of the NG REPIR OR REPLCE HRNESS ND REPLCE INTKE IR FLOW METER SUSSY 189

4 0528 DIGNOSTICS 5 CHECK HRNESS ND (E.F.I. RELYMSS IR FLOW METER) Disconnect the battery negative () terminal. Disconnect the ECM E6 connector. Check continuity between the terminals + of the ECM connector and 3 of the E.F.I. relay installation relay block Check continuity between the terminals G of the mass air flow meter connector and of the NG REPIR OR REPLCE HRNESS ND G CHECK FOR ECM POWER SOURCE CIRCUIT 190

5 DIGNOSTICS INSPECT ECM Check continuity between the terminals and of the NG 7 CHECK HRNESS ND (ECMMSS IR FLOW METER) (e) (f) Check for open between the terminals of the mass air flow meter connector and of the Check for open between the terminals of the mass air flow meter harness connector and of the Disconnect the ECM E3 and E4 connector. Check for short between the terminals and of the Check for short between the terminals and of the NG REPIR OR REPLCE HRNESS ND 191