DTC B1440. Isuzu Isuzu MD F-Series 2005

For 1990-2009 cars only

Makes 🢒 Isuzu 🢒 2005 🢒 Isuzu MD F-Series 🢒 DTC 🢒 DTC B1440

Table 1:	Normal Device Power Moding
Table 2:	Code Setting Criteria -- Fault for Device Power Moding

Circuit Description

Class 2 communications will not start until the vehicle systems ON power mode has been identified. Three discrete wires from the ignition switch contacts are monitored by the instrument panel cluster (IPC) in order to determine the present power mode--ignition switch position. The IPC communicates the system power mode to all class 2 modules on the class 2 serial data line.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B1440 Power Mode Master Input Circuits Mismatch

Conditions for Running the DTC

The IPC must be powered.

Conditions for Setting the DTC

One of the 3 monitored ignition switch circuits has malfunctioned.

Action Taken When the DTC Sets

The IPC implements default actions for each ignition switch position when faults are detected.

Conditions for Clearing the DTC

The power moding malfunction must be corrected and then the code can be cleared by using the scan tool. The code also clears after 100 ignition cycles.

Normal Device Power Moding

Key Position	ACC	IGN 1	IGN 0	Engine Running	Power Mode
OFF/AWAKE	Inactive	Inactive	Inactive	No	OFF/AWAKE
UNLOCK	Inactive	Inactive	Active	No	UNLOCK
CRANK	Inactive	Active	Active	No	CRANK
ACC	Active	Inactive	Inactive	No	ACC
UNLOCK	Active	Inactive	Active	No	UNLOCK
RUN	Active	Active	Active	No	RUN
OFF/AWAKE	Inactive	Inactive	Inactive	Yes	OFF/AWAKE
UNLOCK	Inactive	Inactive	Active	Yes	UNLOCK
RUN	Active	Active	Active	Yes	RUN

Code Setting Criteria -- Fault for Device Power Moding

ACC	IGN 1	IGN 0	Engine Running	Power Mode (Default)
Inactive	Active	Inactive	No	OFF/AWAKE
Active	Active	Inactive	No	RUN
Inactive	Active	Inactive	Yes	RUN
Inactive	Active	Active	Yes	RUN -- Fault is set only if this condition exists for more than 1 minute
Active	Inactive	Inactive	Yes	RUN
Active	Inactive	Active	Yes	RUN
Active	Active	Inactive	Yes	RUN

Step	Action	Yes	No
Schematic Reference: Instrument Cluster Schematics
1	Did you perform the Diagnostic System Check - Vehicle?	Go to Step 2	Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2	Install a scan tool. Turn ON the ignition, with the engine OFF. With the scan tool, observe the Ignition 1 and the Ignition 0 parameters in the instrument panel cluster (IPC) data list. Does the scan tool display Active for both parameters?	Go to Step 3	Go to Step 4
3	Turn the ignition switch to accessory. With the scan tool, observe the Ignition 1 parameter in the IPC data list. Does the scan tool display Inactive?	Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems	Go to Step 5
4	Test the ignition voltage circuit for an open, for a high resistance or for a short to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 8	Go to Step 6
5	Test the ignition 1 voltage circuit for a short to voltage. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 8	Go to Step 6
6	Inspect for poor connections at the harness connector of the IPC. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 8	Go to Step 7
7	Replace the IPC. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement?	Go to Step 8	--
8	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