Isuzu N 2008 Series Workshop Manual page 212

Step
1. Leave the DMM connected to the CMP sensor
harness connector.
2. Turn OFF the ignition.
3. Disconnect the fuel rail pressure (FRP) sensor
5
harness connector.
4. Turn ON the ignition, with the engine OFF.
Does the DMM voltage change to more than the
specified value?
Notice: If no EGR valve is installed, skip to Step 7.
1. Leave the DMM connected to the CMP sensor
harness connector.
2. Turn OFF the ignition.
6
3. Disconnect the EGR valve harness connector.
4. Turn ON the ignition, with the engine OFF.
Does the DMM voltage change to more than the
specified value?
1. Leave the DMM connected to the CMP sensor
harness connector.
2. Turn OFF the ignition.
3. Disconnect the barometric pressure (BARO)
7
sensor harness connector.
4. Turn ON the ignition, with the engine OFF.
Does the DMM voltage change to more than the
specified value?
1. Leave the DMM connected to the CMP sensor
harness connector.
2. Turn OFF the ignition.
3. Disconnect the accelerator pedal position
8
(APP) sensor harness connector.
4. Turn ON the ignition, with the engine OFF.
Does the DMM voltage change to more than the
specified value?
1. Test the 5 volts reference circuit 2 between the
ECM (pin 61 of J14) and the following
components for a short to ground or short to
the low reference circuit:
• APP sensor 2 (pin 1 of B5)
• BARO sensor (pin 3 of B121)
2. Test the 5 volts reference circuit 5 between the
ECM (pin 87 of E12) and the following
9
components for a short to ground or short to
the low reference circuit:
• FRP sensor (pin 3 of E19)
• CMP sensor (pin 3 of E18)
• EGR valve position sensor (pin 1 of E15)
3. Repair the circuit(s) as necessary.
Did you find and correct the condition?
Action
Engine Control System (4JJ1)
Value(s) Yes
4.5 volts
Go to Step 12
4.5 volts
Go to Step 13
4.5 volts
Go to Step 14
4.5 volts
Go to Step 15
—
Go to Step 17
1A-209
No
Go to Step 6
Go to Step 7
Go to Step 8
Go to Step 9
Go to Step 16