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continuity exists, go to next step. 2. Install BOB. Connect ECT. Warm engine to normal operating temperature. Measure resistance between ECT test pin and SIGRTN pins. If resistance is 500-1000 ohms, replace ECA. If resistance is not 500-1000 ohms, replace ECT sensor. PINPOINT TEST VAT - VANE AIR TEMPERATURE SENSOR
Fig. 10: Identifying VAT Circuits
VAT CIRCUIT PIN IDENTIFICATION 1. Turn ignition off. Ensure engine is at operating temperature. With ignition off, install BOB. Turn ignition on. Measure temperature near VAT sensor. Measure voltage between VAT and SIGRTN test pins. Compare voltage to specifications shown in VAT SENSOR VOLTAGE table. If voltage is within specification, VAT circuit is okay. If voltage is not within specification, go to next step. VAT SENSOR VOLTAGE 2. Turn ignition off. Disconnect ECA. Measure resistance between VAT and SIGRTN test pins. Measure temperature near VAF meter. Compare resistance to specifications shown in VAT SENSOR RESISTANCE table. If resistance is within specification, go to next step. If resistance is not within specification, go to step 4). 3. Unplug VAF sensor connector. Measure resistance between VAT test pin and all other test pins. If any resistance is less than 5 ohms, repair VAT wire from ECA to VAF meter. If all measurements are greater than 5 ohms, replace ECA. 4. Turn ignition off. Unplug VAF meter connector. Monitor temperature near VAT sensor. Measure resistance between VAF meter VAT and SIGRTN terminals. Compare resistance to specifications shown in VAT SENSOR RESISTANCE table while heating VAT sensor . If resistance is within specification, repair VAT and/or SIGRTN wires from VAF to ECA. If resistance is not within specification, replace VAT SENSOR RESISTANCE NOTE: Enter this test only when a Code 10 is displayed during QUICK TESTS procedure or when directed here Circuit ECA Pin BOB Pin Wire Color 1.3L GND 2A 46, 49 BLK VAT 2P 45 GRN/BLK 1.6L SIGRTN 2C 46,49 BLU/YEL VAT 2J 25 BRN/YEL Temperature °F (°C) (1) Volts 20 (-6) 3.64 30 (-1) 3.36 40 (4) 3.05 44 (7) 2.79 50 (10) 2.29 60 (16) 2.61 70 (21) 2.35 80 (27) 2.05 90 (32) 1.76 100 (38) 1.57 (1) Values may vary by 15 percent. |