DTC 31 Air Flow Circuit Malfunction

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Shannon O’Brien’
5 years ago
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1 EINE (European Spec.) DI1 DIOW15 DTC 1 Air Flow Circuit Malfunction CIRCUIT DESCRIPTION The 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 A and B remains equal to maintain the set temperature. Thermistor B+ Power Transistor Platinum Hot Wire A B Output Voltage Platinum Hot Wire Thermistor A09782 DTC No. DTC Detection Condition Trouble Area S Open or short in air flow meter circuit 1 Open or short in air flow meter circuit it with more than sec. S Air flow meter S Engine ECU HINT: After confirming DTC 1, use the handheld tester to confirm the air flow ratio from the CURRENT DATA. Air Flow Value (gm/sec.) Approx. 0.0 Malfunction S Air flow meter power source circuit open S VG circuit open or short or more S EVG circuit open 1HDFTE EINE SUP

2 DI2 EINE (European Spec.) WIRI DIAGRAM A20 Air Flow Meter 4 B 11 E16 Engine ECU EVG BY 2 IG2 BY B(LHD) C(RHD) J11(RHD) J59(LHD) J/C BY B(LHD) C(RHD) 17 IN1 Engine Room J/B BY 5 2 YB VR 1 IN4 YB 10 E16 11 E18 VG THAF 7 1C EFI or ECD Relay 1 EFI or ECD 1 1N C BW 8 IG2 BW E19 MREL F17 Fusible Link Block B ALT MAIN 6 EA Battery A HDFTE EINE SUP

3 INSPECTION PROCEDURE EINE (European Spec.) HINT: Read freeze frame data using hand held tester, as freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, etc. at the time of the malfunction. When using handheld tester: 1 Connect handheld tester, and read value of air flow rate. (a) Connect the handheld tester to the DLC. (b) Turn the ignition switch ON and push the held hand tester main switch ON. (c) Start the engine. Read the air flow rate on the hand held tester. RESULT: Type I Type II Air Flow Rata (gm/sec.) or more DI Type I Go to step 2. Type II Go to step 5. 2 Check voltage of air flow meter power source. BE665 S057 ON (+) () A10172 (a) Disconnect the air flow meter connector. (b) Turn the ignition switch ON. Measure the voltage between terminal of the air flow meter connector and body ground. : Voltage: 9 14V Check for open in harness and connector between EFI main relay (Marking: EFI) and air flow meter (See page IN1 9). 1HDFTE EINE SUP

4 DI4 EINE (European Spec.) Check voltage between terminals VG of engine ECU connector and body ground. VG A16788 (a) Remove the glove compartment door. (b) Start the engine. Measure the voltage between terminal VG of the engine ECU connector and body ground while the engine is idling. : Voltage: V (Neutral position and A/C switch OFF) Check and replace engine ECU (See page IN1 9). 4 Check for open and short in harness and connector between air flow meter and engine ECU (See page IN1 9). Repair or replace harness or connector. Replace air flow meter. 1HDFTE EINE SUP

5 EINE (European Spec.) DI5 5 Check continuity between terminal EVG of engine ECU connector and body ground. EVG (a) Remove the glove compartment door. (b) Disconnect the engine ECU connector. Check the continuity between terminal EVG of the engine ECU connector and body ground. : Continuity (1 or less) A1689 Check and replace engine ECU (See page IN1 9). 6 Check for open in harness and connector between air flow meter and engine ECU (See page IN1 9). Repair or replace harness or connector. Replace air flow meter. 1HDFTE EINE SUP

6 DI6 When not using handheld tester: EINE (European Spec.) 1 Check voltage between terminals VG of engine ECU connector and body ground. () (+) VG A16788 (a) Remove the glove compartment door. (b) Start the engine. Measure the voltage between terminal VG of the engine ECU connector and body ground while the engine is idling. : Voltage: V (Neutral position and A/C switch OFF) Check and replace engine ECU (See page IN1 9). 2 Check voltage of air flow meter power source. BE665 S057 ON (+) () A10172 (a) Disconnect the air flow meter connector. (b) Turn the ignition switch ON. Measure the voltage between terminal of the air flow meter connector and body ground. : Voltage: 914 V Check for open in harness and connector between EFI main relay (Marking: EFI) and air flow meter (See page IN1 9). 1HDFTE EINE SUP

7 EINE (European Spec.) DI7 Check for open in harness and connector between air flow meter and engine ECU (See page IN1 9). Repair or replace harness or connector. Replace air flow meter. 1HDFTE EINE SUP

DTC P0100 Mass or Volume Air Flow Circuit. DTC P0102 Mass or Volume Air Flow Circuit Low Input. DTC P0103 Mass or Volume Air Flow Circuit High Input

DTC P0100 Mass or Volume Air Flow Circuit. DTC P0102 Mass or Volume Air Flow Circuit Low Input. DTC P0103 Mass or Volume Air Flow Circuit High Input DI98 DIGNOSTICS EINE (1GRFE) DIDT801 DTC P0100 Mass or Volume ir Flow Circuit DTC P010 Mass or Volume ir Flow Circuit Low Input DTC P0103 Mass or Volume ir Flow Circuit High Input CIRCUIT DESCRIPTION The