Diagnostic Trouble Codes Troubleshooting

DTC TROUBLESHOOTING

Step	Action	Yes	No
1	Was " ENGINE AND EMISSION CONTROL SYSTEM CHECK " performed?	Go to Step 2.	Go to "ENGINE AND EMISSION CONTROL SYSTEM CHECK :".
2	Visual inspection Check MAF and IAT sensor and air intake system for: Objects which block measuring duct and resistor of MAF and IAT sensor. Other air flow which does not pass the MAF and IAT sensor. Are there in good condition?	Go to Step 3.	Repair or replace.
3	MAF and IAT sensor performance check With ignition switch turned OFF, connect scan tool to DLC. Start engine and warm up to normal operation temp. Check MAF value using scan tool, under the following conditions. MAF value specification Idling: 1.5-4.0 g/sec. Racing at 2500 r/min: 5.0 - 10.0 g/sec. Is each value as specified?	Go to Step 11.	Go to Step 4.
4	MAF and IAT sensor output voltage check Check voltage between "C46-29" and "G04-15" terminals of ECM connector under the following conditions. Voltage between "C46-29" and "G04-15" terminal of ECM connector Ignition switch ON, leaving engine OFF: 0.5 - 1.0 V Idling: 1.3-1.8V Is each value as specified?	Poor "C46-29" or/and "G04-15" terminal connection. If OK, substitute a known-good ECM and recheck.	Go to Step 5.
5	Check MAF and IAT sensor power supply voltage Disconnect connector (3) from MAF a with ignition switch turned OFF. Turn ON ignition switch, measure voltage between engine ground and "BLK/RED" wire terminal (2) of MAF and IAT sensor connector. Is voltage 10 - 14 V?	Go to Step 6.	Open wire in "BLK/RED" circuit.
6	Check MAF and IAT sensor ground circuit Measure resistance between "ORN" wire terminal of MAF and IAT sensor connector and engine ground. Is resistance below 5 Ω?	Go to Step 8.	Go to Step 7.
7	Check ground circuit Disconnect connectors from ECM with ignition switch turned OFF. Remove ECM from vehicle body and connect connectors to ECM. Measure resistance between "G04-15" terminal of ECM connector and vehicle body ground. Is resistance below 5 Ω?	Open or high resistance wire in "ORN" circuit.	Open or high resistance wire in "C45-6" and/or "C46-6" circuit. If wires are OK, substitute a known-good ECM and recheck.
8	Check MAF and IAT sensor signal circuit Turn ON ignition switch. Measure voltage between "GRN" wire terminal of MAF and IAT sensor connector and engine ground. Is voltage 0 V?	Go to Step 9.	"GRN" wire shorted to other circuits.
9	Check MAF and IAT sensor signal circuit Disconnect connectors from ECM with ignition switch turned OFF. Measure resistance between "GRN" wire terminal of MAF and IAT sensor connector and vehicle body ground. Is resistance infinity?	Go to Step 10.	"GRN" wire shorted to ground circuit.
10	Check MAF and IAT sensor signal circuit Measure resistance between "GRN" wire terminal of MAF and IAT sensor connector and "G04-15" terminal of ECM connector. Is resistance below 3 Ω?	Faulty MAF and IAT sensor.	Open or high resistance wire in "GRN" circuit.
11	MAP sensor performance check Connect connectors to ECM and MAF and IAT sensor with ignition switch turned OFF. Check voltage between "C45-20" and "C46-16" terminals of ECM connector. Voltage between "C45-20" and "C46-16" terminals of ECM connector Ignition switch ON, leaving engine OFF: 3.3 - 4.3 V at barometric pressure 100 kPa (760 mmHg) Idling: 0.7 - 1.6 V at barometric pressure 100 kPa (760 mmHg) Is each value satisfied?	Substitute a known-good ECM and recheck.	MAP performance problem. Check MAP sensor referring to "MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR INSPECTION ".