Isuzu N 2008 Series Workshop Manual page 149

1A-146 Engine Control System (4JJ1)
Step
Is the DMM voltage more than the specified value
6
at Step 5?
1. Connect a test lamp between the signal circuit
(pin 1 of E18) and a known good ground.
2. Connect a DMM between the probe of the test
7
lamp and a known good ground.
Is the DMM voltage more than the specified value?
Connect a DMM between the 5 volts reference
circuit and low reference circuit of (pins 2 and 3 of
8
E18).
Is the DMM voltage more than the specified value?
Notice: The CMP 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
9
ECM (pin 87 of E12) and the CMP sensor (pin
3 of E18) for an open circuit or high
resistance.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition?
Notice: The CMP sensor shares the low reference
circuit with other sensors. A fault condition in the
low reference circuit may set DTCs on sensors that
share this circuit.
1. Test the low reference circuit between the
10
ECM (pin 101 of E12) and the CMP sensor
(pin 2 of E18) 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
98 of E12) and the CKP sensor (pin 1 of E18)
for the following conditions:
• An open circuit
• A short to ground
11
• A short to the low reference circuit
• High resistance
2. Repair the circuit(s) as necessary.
Did you find and correct the condition?
Important: The CMP sensor may be damaged if
the sensor signal circuit is shorted to a voltage
source.
1. Test the signal circuit between the ECM (pin
12
98 of E12) and the CMP sensor (pin 1 of E18)
for a short to battery or ignition voltage.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition?
1. Test the signal circuit between the ECM (pin
98 of E12) and the CMP sensor (pin 1 of E18)
for a short to any 5 volts reference.
13
2. Repair the circuit(s) as necessary.
Did you find and correct the condition?
Action Value(s) Yes
4.5 volts
Go to Step 7
4.5 volts
Go to Step 13
4.5 volts
Go to Step 14
—
Go to Step 19
—
Go to Step 19
—
Go to Step 19
—
Go to Step 19
—
Go to Step 19
No
Go to Step 11
Go to Step 8
Go to Step 10
Go to Step 15
Go to Step 15
Go to Step 15
Go to Step 18
Go to Step 18