Isuzu Rodeo UE. Manual - part 649

9J1–33

RESTRAINT CONTROL SYSTEM

DTC 25 Driver Deployment Loop Short To Voltage

D09RW002

Circuit Description:

DTC Will Set When:

“Ignition 1” is in the normal operating voltage range. This
test is run once each ignition cycle and “Continuous
Monitoring”. Once these conditions are met and the
voltage at “Driver Bag Low” is above a specified value,
DTC 25 will set.

Action Taken:

SDM turns “ON” the “AIR BAG” warning lamp and sets
DTC 25 and also DTC 71

DTC Will Clear When:

The SDM is replaced.

DTC Chart Test Description:

Number(s) below refer to step number(s) on the
diagnostic chart:
2. This test determines whether the SDM is

malfunctioning.

3. This test isolates the malfunction to one side of the

SRS coil assembly yellow 2–pin connector at the
base of steering column.

4. This test determines whether the malfunction is in

CKT IB05–YEL.

5. This test determines whether the malfunction is in

CKT IB06–YEL/BLK.

RESTRAINT CONTROL SYSTEM

9J1–34

6. This test determines whether the malfunction is in

the SRS coil assembly or the driver air bag
assembly.

Diagnostic Aids:

An intermittent condition is likely to be caused by a short
to B+ in the driver air bag assembly circuit. Inspect CKTs
IB05–YEL and IB06–YEL/BLK carefully for cutting or
chafing. If the wiring pigtail of the driver air bag assembly
and SRS coil assembly is damaged, the components
must be replaced. A careful inspection of CKT IB05–YEL
and IB06–YEL/BLK, including the SRS coil assembly and
driver air bag assembly is essential to ensure that the
replacement SDM will not be damaged.

9J1–35

RESTRAINT CONTROL SYSTEM

DTC 25 Driver Deployment Loop Short To Ignition

CAUTION: When DTC 25 has been set, it is necessary to replace the SDM. Setting DTC 25 will also cause DTC
71 to set. When a scan tool “CLEAR CODES” command is issued and the malfunction is no longer present,
DTC 71 will remain current. Ensure that the short to voltage condition is repaired prior to installing a
replacement SDM to avoid damaging the SDM.

Step

Action

Yes

Was the “SRS Diagnostic System Check” performed?

Go to Step 2

Go to the “SRS

Diagnostic

System Check.”

1. When measurements are requested in this chart use J–39200

DVM with correct terminal adapter from J–35616–A.

2. Ignition switch “OFF.”
3. Connect scan tool data link connector. Follow directions as

given in the scan tool operator’s manual.

4. Ignition switch “ON.”
5. Read driver sense LO.

Is driver sense LO more than 3.5 volts?

Go to Step 3

Go to Chart A.

1. Ignition switch “OFF.”
2. Disconnect SRS coil assembly yellow 2–pin connector at the

base of the steering column. Leave passenger air bag
assembly connected.
Connect SRS driver / passenger load tool J–41433 and
appropriate adapter to SRS coil assembly harness connector.

3. Ignition switch “ON.”

Is driver sense LO more than 3.5 volts?

Go to Step 4

Go to Step 6

1. Ignition switch “OFF.”
2. Disconnect SDM.
3. Disconnect SRS drive / passenger load tool.
4. Measure resistance on SDM harness connector from terminal

“3” to terminal “12” (Ignition 1).

Does J–39200 display “0L” (infinite)?

Go to Step 5

Replace SRS

harness.

Go to Step 7

Measure resistance on SDM harness connector from terminal “4”
to terminal “12” (Ignition 1).

Does J–39200 display “0L” (infinite)?

Go to Chart A.

Replace SRS

harness.

Go to Step 7

1. Ignition switch “OFF.”
2. Connect SRS driver / passenger load tool J–41433 and

appropriate adapter J–35616–A to driver air bag assembly
harness connector located of top of the steering column.

3. Reconnect SRS coil assembly harness connector as the base

of steering column.

4. Ignition switch “ON.”

Is driver sense LO more than 3.5 volts?

Ignition switch

“OFF.”

Replace SRS coil

assembly.

Go to Step 7

Ignition switch

“OFF.”

Replace driver air

bag assembly.

Go to Step 7

1. Reconnect all components, ensure all components are

properly mounted.

2. Ignition switch “ON.”

Is passenger sense LO less than 3.5 volts?

Replace SDM.

Go to Step 8

Go to Chart A.

1. Reconnect all components, ensure all components are

properly mounted.

2. Clear diagnostic trouble codes.

Was this step finished?

Repeat the “SRS

Diagnostic

System Check.”

Go to Step 8

RESTRAINT CONTROL SYSTEM

9J1–36

DTC 26 Driver Deployment Loop Open

D09RW002

Circuit Description:

When the ignition switch is turned “ON”, the SDM will
perform tests to diagnose critical malfunctions within
itself. Upon passing these tests, “ignition 1”, and
deployment loop voltages are measured to ensure they
are within their respective normal voltage ranges.
During “Continuous Monitoring” diagnostics, a fixed
amount of current is following in the deployment loop.
This produces proportional voltage drops in the loop. By
monitoring the voltage difference between “Driver Bag
High” and “Driver Bag Low”, the SDM calculates the
combined resistance of the driver air bag assembly, SRS
coil assembly, harness wiring CKTs IB05–YEL and
IB06–YEL/BLK, and connector terminal contact.

DTC Will Set When:

The voltage difference between “Driver Bag High”
terminal “3” and “Driver Bag Low” terminal “4” is above or

equal to a specified value for 500 milliseconds during
“Continuous Monitoring.”

Action Taken:

SDM turns “ON” the “AIR BAG” warning lamp and sets a
diagnostic trouble code.

DTC Will Clear When:

The voltage difference between “Driver Bag High”
terminal “3” and “Driver Bag Low” terminal “4” is below a
specified value for 500 milliseconds during “Continuous
Monitoring.”

DTC Chart Test Description:

Number(s) below refer to circled number(s) on the
diagnostic chart:
1. This test determines whether the malfunction is in

the SDM.

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