Pinpoint Test Vat - Vane Air Temperature Sensor

NOTE: Enter this test only when a Code 10 is displayed during QUICK TESTS procedure or when directed here from another PINPOINT TEST. Ambient temperature must be higher than 50°F (10°C) for this test.

Fig 1: Identifying VAT Circuits

VAT CIRCUIT PIN IDENTIFICATION

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

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

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.

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).
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.
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 VAF meter.

VAT SENSOR RESISTANCE

Temperature °F (°C)	Ohms
-4 (-23)	15,000
32 (0)	5210
68 (20)	2500
104 (40)	1100
140 (60)	600
176 (80)	300