Circuit Description
The instrument panel module (IPM) is the power mode master and the remote control door lock receiver (RCDLR) is the backup power mode master. Both modules receive information regarding ignition mode switch position from the ignition mode switch. The ignition mode switch will be monitored only with battery voltage at or above 7 volts to prevent invalid input readings during low voltages encountered during vehicle cranking.
Four modes are discernible:
| • | Inactive |
| • | Start active |
| • | Off active |
| • | Short detect |
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B1440 Power Mode Master Input Circuits Mismatch
DTC Symptom | DTC Symptom Descriptor |
|---|---|
03 | Voltage Below Threshold |
08 | Signal Invalid |
Conditions for Running the DTC
Voltage supplied to the module is in the normal operating voltage range of 9-16 volts.
Conditions for Setting the DTC
B1440 03
The RCDLR detects a short to ground on its mode data input circuit, for more than 60 seconds.
B1440 08
| • | The RCDLR input does not match the state of the mode switch received from the IPM. |
| • | The RCDLR receives a message from the IPM, indicating that a switch has been pressed, without seeing the corresponding input go active. |
| • | The RCDLR mode data input is active for more than 60 seconds, without seeing the corresponding message from the IPM. |
Action Taken When the DTC Sets
The Service Vehicle Soon (SVS) indicator will illuminate. Also, the following scenarios may take place:
| • | If the RCDLR senses a change on its ignition mode data input, but does not receive the corresponding message from the IPM, the RCDLR will enable the backup power mode. The backup power mode will be the old power mode. If a second change is sensed by RCDLR on its ignition mode data input, without the corresponding message from the BCM, the backup power mode will be changed accordingly to signal sensed. |
| • | If the RCDLR receives a message from the IPM, indicating that a switch has been pressed, without sensing the change itself, the setting of the backup power moding will be disabled for the current ignition cycle. |
Conditions for Clearing the DTC
| • | A current DTC clears when the malfunction is no longer present. |
| • | A history DTC clears when the module ignition cycle counter reaches the reset threshold, without a repeat of the malfunction. |
Diagnostic Aids
The setting of this DTC can be caused by various failures:
| • | The RCDLR malfunction |
| • | The IPM malfunction |
| • | The ignition mode switch malfunction |
| • | The ignition mode data input circuits to either RCDLR or IPM |
Test Description
The number below refers to the step number on the diagnostic table.
Step | Action | Values | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Power Distribution Schematics Connector End View Reference: Master Electrical Component List | ||||||||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |||||||
2 | Did you retrieve any of the following DTCs?
| -- | Go to Step 3 | |||||||
Does the parameter value toggle between Idle and ACC/OFF and between Idle and Run respectively? | -- | Go to Step 4 | Go to Step 11 | |||||||
4 |
Is the voltage measured within the specified range? | B+ | Go to Step 5 | Go to Step 6 | ||||||
5 | Measure the voltage between the IPM ignition mode switch reference voltage circuit and the IPM ignition mode signal circuit at the ignition mode switch connector. Is the voltage measured within the specified range? | B+ | Go to Step 7 | Go to Step 8 | ||||||
6 |
Did you find and correct the condition? | -- | Go to Step 25 | Go to Step 21 | ||||||
7 |
Did you find and correct the condition? | -- | Go to Step 25 | Go to Step 9 | ||||||
8 |
Did you find and correct the condition? | -- | Go to Step 25 | Go to Step 21 | ||||||
9 | While measuring the resistance between the IPM ignition mode data signal and IPM ignition mode switch reference voltage circuits at the ignition mode switch, press the OFF/ACC button of the ignition mode switch. Is the value measured approximately as specified? | 270 ohms | Go to Step 10 | Go to Step 23 | ||||||
10 | While measuring the resistance between the IPM ignition mode data signal and IPM ignition mode switch reference voltage circuits at the ignition mode switch, press the START button of the ignition mode switch. Is the value measured approximately as specified? | 450 ohms | Go to Step 21 | Go to Step 23 | ||||||
11 |
Is the voltage measured within the specified range? | B+ | Go to Step 12 | Go to Step 14 | ||||||
12 | Install a test lamp between the RCDLR ignition mode data signal circuit at the ignition mode switch connector and a good ground. Does the test lamp illuminate? | -- | Go to Step 15 | Go to Step 13 | ||||||
13 | Measure the voltage between the RCDLR ignition mode data signal circuit and the RCDLR ignition mode ground circuit at the ignition mode switch connector. Is the voltage measured within the specified range? | B+ | Go to Step 17 | Go to Step 16 | ||||||
14 |
Did you find and correct the condition? | -- | Go to Step 25 | Go to Step 19 | ||||||
15 |
Did you find and correct the condition? | -- | Go to Step 25 | Go to Step 19 | ||||||
16 |
Did you find and correct the condition? | -- | Go to Step 25 | Go to Step 19 | ||||||
17 | While measuring the resistance between the RCDLR ignition mode data signal and RCDLR ignition mode ground circuits at the ignition mode switch press the ACC/OFF button of the ignition mode switch. Is the value measured approximately as specified? | 2,000 ohms | Go to Step 18 | Go to Step 23 | ||||||
18 | While measuring the resistance between the RCDLR ignition mode data signal and RCDLR ignition mode ground circuits at the ignition mode switch press the START button of the ignition mode switch. Is the value measured approximately as specified? | 0 ohms | Go to Step 19 | Go to Step 23 | ||||||
19 | Inspect for poor connections and terminal tension at the harness connector of the RCDLR module. Refer to Testing for Intermittent Conditions and Poor Connections . Did you find and correct the condition? | -- | Go to Step 25 | Go to Step 20 | ||||||
20 | Replace the RCDLR module. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 25 | -- | ||||||
21 | Inspect for poor connections and terminal tension at the harness connector of the IPM. Refer to Testing for Intermittent Conditions and Poor Connections . Did you find and correct the condition? | -- | Go to Step 25 | Go to Step 22 | ||||||
22 | Replace the IPM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 25 | -- | ||||||
23 | Inspect for poor connections and terminal tension at the harness connector of the ignition mode switch. Refer to Testing for Intermittent Conditions and Poor Connections . Did you find and correct the condition? | -- | Go to Step 25 | Go to Step 24 | ||||||
24 | Replace the ignition mode switch. Refer to Ignition and Start Switch Replacement . Did you complete the replacement? | -- | Go to Step 25 | -- | ||||||
25 |
Does the DTC reset? | -- | Go to Step 3 | System OK | ||||||
