Diagnosis & Repair
- Connect Toyota hand-held tester or scan tool to Data Link Connector (DLC) No. 3. See Figure. Turn ignition on and then turn hand-held tester or scan tool on. Start engine and allow engine to idle. Using hand-held tester or scan tool, monitor MAF meter air flow rate. If MAF meter air flow rate is 0.0 gm/sec., go to next step. If MAF meter air flow rate is 271 gm/sec. or more, go to step 5.
- Turn ignition off. Disconnect MAF meter harness connector. Turn ignition on. Measure voltage between ground and terminal No. 1 (Black/Yellow wire) at MAF meter harness connector. See Fig 1. If voltage is 9-14 volts, go to next step. If voltage is not 9-14 volts, repair open in Black/Yellow wire between EFI relay and MAF meter. See WIRING DIAGRAMS
article.
- Turn ignition off. Connect MAF meter harness connector. Access ECM behind glove box. See Figure. Ensure shift lever is in Neutral or Park. Ensure A/C switch is OFF. Start engine and allow engine to idle. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 2 (Pink wire) at ECM harness connector E6. See Figure. If voltage is not 1.1-1.5 volts, go to next step. If voltage is 1.1-1.5 volts, replace ECM.
- Check for open or short in Pink wire between MAF meter and ECM. See WIRING DIAGRAMS
article. If problem exists, repair wiring as necessary. If problem does not exist, replace MAF meter.
- Turn ignition off. Access ECM behind glove box. See Figure. Using DVOM, backprobe ECM harness connector and measure resistance between ground and terminal No. 10 (Violet wire) at ECM harness connector E6. See Figure. If resistance is one ohm or less, go to next step. If resistance is greater than one ohm, replace ECM.
- Check for open in Violet wire between MAF meter and ECM. See WIRING DIAGRAMS
article. If problem exists, repair wiring as necessary. If problem does not exist, replace MAF meter.
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