Isuzu 2008MY N Series Workshop Manual page 132

Step
1. Test the signal circuits between the ECM (pins
82 and 90 of E-12) and the FRP sensor (pin 2
of E-19) for the following conditions:
• A short to ground
6
• A short to the low reference circuit
2. Repair the circuit(s) as necessary.
Did you find and correct the condition?
Notice: The FRP sensor 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
7
ECM (pin 87 of E-12) and the FRP sensor (pin
3 of E-19) for an open circuit or high
resistance.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition?
1. Inspect for an intermittent and for a poor
connection at the harness connector of the
FRP sensor (pin 3 of E-19).
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 a poor
connection at the harness connector of the
9
ECM (pin 87 of E-12).
4. Repair the connection(s) as necessary.
Did you find and correct the condition?
Replace the FRP sensor. Refer to Fuel Pressure
Sensor in Section 1D Engine Fuel.
10
Did you complete the replacement?
Important: Replacement
programmed.
11
Replace the ECM. Refer to ECM Replacement.
Did you complete the replacement?
1. Reconnect
harness connector(s).
2. Clear the DTCs with a scan tool.
3. Turn OFF the ignition for 30 seconds.
4. Start the engine.
12
5. Operate the vehicle within the Conditions for
Running the DTC. You may also operate the
vehicle within
observed from the Freeze Frame/ Failure
Records.
Did the DTC fail this ignition?
Observe the DTC Information with a scan tool.
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Are there any DTCs that you have not
diagnosed?
Action
ECM must
all previously disconnected
the conditions that
Engine Control System (4HK1)
Value(s)
—
—
—
—
—
be
—
—
you
—
Yes
Go to Step 12 Go to Step 11
Go to Step 12 Go to Step 9
Go to Step 12 Go to Step 10
Go to Step 12 Go to Step 11
Go to Step 12
Go to Step 12
Go to Step 3 Go to Step 13
Go to DTC List
1A-129
No
—
—
System OK