Ambient Air Temperature Sensor, Checking

Special tools and workshop equipment required 

• multimeter.
• Wiring diagram.

Test procedure 

-- Perform a preliminary check to verify the customers complaint. Refer to PRELIMINARY CHECK 

Start diagnosis 

-- Connect the scan tool.

-- Engine MUST be at room temperature.

-- Switch the ignition on.

-- Using the scan tool, check the ambient air temperature:

Diagnostic text		Specified value
Ambient Air Temperature (AAT)		approx. ambient air temperature

If the specified value was obtained:

-- Fault may be intermittent. Check for proper connection, damaged wiring or loose terminals.

If the specified value was Not obtained:

Checking internal resistance 

-- Turn the key off.

-- Disconnect the Ambient Air Temperature Sensor -G17- electrical harness connector.

-- Using a multimeter, check the Ambient Air Temperature Sensor -G17- terminals 1 to 2 for resistance.

Use the chart below for the specified values:

Specified values:

AAT Temperature vs Resistance
Temp (C)	min. value ohms	max. value ohms
- 40	31811	37560
- 35	22941	26863
- 25	12415	14289
- 15	6958	7880
- 5	4036	4495
0	3120	3442
5	2422	2655
15	1519	1623
25	968	1031
35	629	676
45	419	455
55	286	314
65	195	217
75	136	155

If the specified values were Not obtained:

-- Replace the Ambient Air Temperature Sensor -G17-. Refer to the appropriate service information.

If the specified values are obtained, continue the test according to the following table:

Checking wiring 

-- Turn the key on.

-- Connect a multimeter to terminals 1 and 2 of the Ambient Air Temperature Sensor -G17- electrical harness connector.

Specified value: near 5.02 V

If the specified value was Not obtained:

-- Turn the key off.

-- Remove the Instrument Cluster. Refer to the appropriate service information.

-- Disconnect the Instrument Cluster harness.

-- Using a multimeter, check the Ambient Air Temperature Sensor -G17- electrical harness connector terminals 1 and 2 to the Instrument Cluster electrical harness connector T36 for an open circuit or a short, refer to the appropriate wiring diagram.

Ambient Air Temperature Sensor -G17- electrical harness connector terminals	Instrument Cluster -J285- electrical connector T32 terminals
1	28
2	24

Specified value: 1.5 Ω max.

If the specified value was obtained:

Replace the Instrument Cluster. Refer to the appropriate service information.

If the specified value was Not obtained:

-- Check the wiring for an open, high resistance or short circuit to Battery (+) or ground.

-- Check the electrical harness connector for damage, corrosion, loose or broken terminals.

-- If necessary, repair the faulty wiring connection.

Final procedures 

After the repair work, the following work steps must be performed in the following sequence:

1. Check the DTC memory. Refer to DIAGNOSTIC MODE 03 - READ DTC MEMORY .
2. If necessary, erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .
3. If the DTC memory was erased, generate readiness code. Refer to READINESS CODE .