Isuzu N 2008 Series Workshop Manual page 84

Step
1. Turn OFF the ignition.
2. Connect a test lamp between the low side
circuit (pin 2 of E17) and battery voltage.
6
3. Turn ON the ignition, with the engine OFF.
Does the test lamp illuminate?
1. Test the high side circuits between the ECM
(pins 105 and 113 of E12) and the FRP
regulator (pin 1 of E17) for a short to battery or
7 ignition voltage.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition?
1. Test the low side circuits between the ECM
(pins 89 and 97 of E12) and the FRP regulator
(pin 2 of E17) for a short to ground.
8
2. Repair the circuit(s) as necessary.
Did you find and correct the condition?
1. Test the high side circuits between the ECM
(pins 105 and 113 of E12) and the FRP
regulator (pin 1 of E17) for the following
conditions:
• An open circuit
9 • A short to ground
• A short to the low side circuit
• High resistance
2. Repair the circuit(s) as necessary.
Did you find and correct the condition?
Important: The ECM may be damaged if the FRP
regulator low side circuit is shorted to a voltage
source.
1. Test the low side circuits between the ECM
(pins 89 and 97 of E12) and the FRP regulator
(pin 2 of E17) for the following conditions:
10
• An open circuit
• A short to battery or ignition voltage
• 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
FRP regulator (pins 1 and 2 of E17).
11
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
12
ECM (pins 89, 97, 105 and 113 of E12).
4. Repair the connection(s) as necessary.
Does the test lamp illuminate then go out?
Action
Engine Control System (4JJ1)
Value(s) Yes
—
Go to Step 11
—
Go to Step 15
—
Go to Step 15
—
Go to Step 15
—
Go to Step 15
—
Go to Step 15
—
Go to Step 15
1A-81
No
Go to Step 10
Go to Step 14
Go to Step 14
Go to Step 12
Go to Step 12
Go to Step 13
Go to Step 14