Isuzu 2008MY N Series Workshop Manual page 261

1A-258 Engine Control System (4HK1)
Step
1. Turn OFF the ignition.
2. Disconnect
connector.
3. Connect a DMM between the 5 volts reference
circuit (pin 4 of B-5) and a known good
4
ground.
4. Turn ON the ignition, with the engine OFF.
Is the DMM voltage more than the specified
value?
Connect a 3-amp fused jumper wire between the 5
volts reference circuit and the signal circuit (pins 4
and 5 of B-5).
5
Is the APP Sensor 1 parameter more than the
specified value?
Notice: The APP sensor 1 shares the 5 volts
reference circuit with other sensors. A fault
condition in the 5 volts reference circuit may set
DTCs on sensors that share this circuit.
1. Test the 5 volts reference circuit between the
6
ECM (pin 42 of J-14) and the APP sensor (pin
4 of B-5) for an open circuit or high resistance.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition?
1. Test the signal circuit between the ECM (pin
63 of J-14) and the APP sensor (pin 5 of B-5)
for the following conditions:
• An open circuit
• A short to ground
7
• A short to the low reference circuit
• High resistance
2. Repair the circuit(s) as necessary.
Did you find and correct the condition?
1. Inspect for an intermittent and for poor
connections at the harness connector of the
APP sensor (pins 4 and 5 of B-5).
8
2. Repair the connection(s) as necessary.
Did you find and correct the condition?
1. Turn OFF the ignition.
2. Disconnect the ECM harness connector.
3. Inspect for an intermittent and for poor
connections at the harness connector of the
9
ECM (pins 42 and 63 of J-14).
4. Repair the connection(s) as necessary.
Did you find and correct the condition?
Replace the APP sensor. Refer to Accelerator
Pedal Sensor in Section 1I Engine Speed Control
10
System.
Did you complete the replacement?
Action
the APP sensor harness
Value(s) Yes
4.5 volts
Go to Step 5
4.5 volts
Go to Step 8
—
Go to Step 12
—
Go to Step 12
—
Go to Step 12
—
Go to Step 12
—
Go to Step 12
No
Go to Step 6
Go to Step 7
Go to Step 9
Go to Step 9
Go to Step 10
Go to Step 11
—