DTC B0490 Passenger Temperature Control Cooler/Warmer Switch Circuit Range. Buick LeSabre 2000

For 1990-2009 cars only

Makes 🢒 Buick 🢒 2000 🢒 LeSabre 🢒 HVAC 🢒 HVAC Systems - Automatic 🢒 DTC B0490 Passenger Temperature Control Cooler/Warmer Switch Circuit Range

HVAC Components
Passenger Side Climate Control W/CJ2
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice
Simple Bus Interface
Serial Data Class 2

Circuit Description

The passenger temperature controls are simple momentary contact switches that connect a series of resistors so that each switch selection corresponds to a fixed resistance value. The front passenger door module (FPDM) determines which switch has been pressed by the voltage drop across the corresponding resistance value. The FPDM converts this input to a digital signal and communicates it to the driver door module (DDM) over the simple bus interface (SBI). The DDM is responsible for the class 2 interface and setting the DTC.

Conditions for Running the DTC

The ignition is turned ON.

Conditions for Setting the DTC

•	The DDM detects that the signal circuit of the passenger HVAC switch is less than 0.09 V (5 counts) or greater than 4.90 V (250 counts).

•	The DDM detects that the passenger cooler or warmer switch is active for greater than 30 seconds.

Action Taken When the DTC Sets

The DDM will ignore the switch command.

Conditions for Clearing the DTC

•	The DTC will become history if the DDM no longer detects a failure.

•	The history DTC will clear after 50 fault free ignition cycles.

•	The DTC can be cleared with a scan tool.

Diagnostic Aids

•	When the warmer (red) switch is active, the input to the DDM is 2.50-3.09V (127-158 counts).

•	When the cooler (blue) switch is active, the input to the DDM is 0.99-1.58V (51-81 counts).

•	When neither switch is active, the input to the DDM is 3.99-4.58V (204-234 counts).

•	Refer to Testing for Intermittent Conditions and Poor Connections .

Test Description

The numbers below refer to the step numbers on the diagnostic table.

The value given is the normal condition that exists when no switch is activated.

Tests for the proper operation of the circuit in the high voltage range.

Tests for the proper operation of the circuit in the low voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to voltage.

Step	Action	Values	Yes	No
1	Did you perform the HVAC Diagnostic System Check?	--	Go to Step 2	Go to Diagnostic System Check
2	Install a scan tool. Turn ON the ignition, with the engine OFF. With a scan tool, observe the Pass. HVAC Switch parameter in the Driver Door Module data list. Does the scan tool indicate that the Pass. HVAC Switch parameter is within the specified range?	204-234 counts	Go to Diagnostic Aids	Go to Step 3
3	Turn OFF the ignition. Disconnect the passenger HVAC switch. Turn ON the ignition, with the engine OFF. With a scan tool, observe the Pass. HVAC Switch parameter. Does the scan tool indicate that the Pass. HVAC Switch parameter is greater than the specified value?	250 counts	Go to Step 4	Go to Step 5
4	Turn OFF the ignition. Connect a 3-amp fused jumper wire between the signal circuit of the passenger HVAC switch and the ground circuit of the passenger HVAC switch. Turn ON the ignition, with the engine OFF. With a scan tool, observe the Pass. HVAC Switch parameter. Does the scan tool indicate that the Pass. HVAC Switch parameter is less than the specified value?	5 counts	Go to Step 8	Go to Step 6
5	Test the signal circuit of the passenger HVAC switch for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	--	Go to Step 12	Go to Step 9
6	Test the signal circuit of the passenger HVAC switch for a short to voltage, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	--	Go to Step 12	Go to Step 7
7	Test the ground circuit of the passenger HVAC switch for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	--	Go to Step 12	Go to Step 9
8	Inspect for poor connections at the harness connector of the passenger HVAC switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?	--	Go to Step 12	Go to Step 10
9	Inspect for poor connections at the harness connector of the front passenger door module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?	--	Go to Step 12	Go to Step 11
10	Replace the passenger HVAC switch. Refer to Instrument Panel Module Replacement . Did you complete the replacement?	--	Go to Step 12	--
11	Replace the front passenger door module. Refer to Door Control Module Replacement in Doors. Did you complete the replacement?	--	Go to Step 12	--
12	Use the scan tool in order to clear the DTCs. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text. Does the DTC reset?	--	Go to Step 2	System OK