Incorrect Outside Air Temperature Display

WARNING: This page is about a different car, the 1996 Buick Roadmaster. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Before proceeding with this test, A/C DIAGNOSTIC SYSTEM CHECK must be performed first.

NOTE: When all diagnosis and repairs are completed, clear DTCs and verify proper system operation.

Enter diagnostics. Select pointer number "-31" (outside air temperature sensor input). Display and record value. Compare resistance value and outside air temperature. See OUTSIDE AIR TEMPERATURE SENSOR SPECIFICATIONS table. If resistance is within specifications, go to next step. If resistance is not within specifications, go to step 4).

OUTSIDE AIR TEMPERATURE SENSOR SPECIFICATIONS

Vehicle Inside Air Temp. °F (°C) ⁽¹⁾

Temp. Sensor ⁽²⁾ Ohms

Outside Air Temp. Input No. "-31"

23 (-5)

12,282

174

32 (0)

9407

158

41 (5)

7273

143

50 (10)

5666

127

59 (15)

4447

112

68 (20)

3514

77 (25)

2795

86 (30)

2237

95 (35)

1802

104 (40)

1459

⁽¹⁾	Plus or minus 5°F (3°C)

⁽²⁾	Resistance values are approximate.

Allow sufficient time for system to update sensor readings. This requires that ignition be turned off for more than 3 hours, or if ignition is turned off for less than 3 hours, engine coolant must be within 50°F (10°C) of outside temperature. If these conditions are not met, outside temperature displayed during previous ignition cycle will be displayed. Enter diagnostics. Select pointer number "-31." Display and record values. Compare resistance value and outside air temperature. See OUTSIDE AIR TEMPERATURE SENSOR SPECIFICATIONS table. If specifications are correct, go to next step. If specifications are not correct, replace A/C-heater control panel.
Incorrect temperature display may be an intermittent problem. Check for historical DTC 01 or 02. While these DTCs are current, the A/C-heater control panel will use a default temperature. See POINTER NUMBER PARAMETERS IDENTIFICATION table. There will be no indication that these DTCs occurred other than incorrect temperature display. Enter diagnostic display and retrieve DTCs. Tap on outside of sensor and wiggle sensor wiring and connectors. If DTC 01 or 02 sets, repair connector or replace outside air temperature sensor.
Exit diagnostics. Disconnect outside air temperature sensor connector. Measure resistance across sensor terminals. Compare resistance value and outside air temperature. See OUTSIDE AIR TEMPERATURE SENSOR SPECIFICATIONS table.
If specifications are not correct, replace sensor. If specifications are correct, remove A/C-heater control panel. Check for poor connections and/or excessive resistance in Light Green/Black and Yellow wires. If resistance and connections are okay, replace the A/C-heater control panel.