Isuzu 4JA1 Workshop Manual page 432

6E-178 Engine Control System (4JH1)
Step
6 Is the DMM voltage less than the specified value at
step 5?
7 Important: The APP sensor may be damaged if the
sensor signal circuit is shorted to a voltage source.
1. Test the signal circuit between the engine control
module (ECM) (pin 35 of C-56 connector) and
the APP sensor (pin 2 of E-22 connector) for the
following conditions:
•
A short to battery or ignition voltage
•
A short to any 5 volts reference
2. Repair the circuit(s) as necessary.
Did you find and correct the condition?
8 1. Test the low reference circuit between the ECM
(pin 47 of C-56 connector) and the APP sensor
(pin 1 of E-22 connector) for an open circuit or
high resistance.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition?
9 1. Test the 5 volts reference circuit between the
ECM (pin 55 of C-56 connector) and the APP
sensor (pin 3 of E-22 connector) for the following
conditions:
•
A short to ground
•
A short to the low reference circuit
2. Repair the circuit(s) as necessary.
Did you find and correct the condition?
10 1. Test the 5 volts reference circuit between the
ECM (pin 55 of C-56 connector) and the APP
sensor (pin 3 of E-22 connector) for a short to
battery or ignition voltage.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition?
11 1. Turn OFF the ignition.
2. Inspect for an intermittent and for a poor
connection at the harness connector of the APP
sensor (pin 1 of E-22 connector).
3. Repair the connection(s) as necessary.
Did you find and correct the condition?
12 1. Turn OFF the ignition.
2. Disconnect the ECM harness connector.
3. Inspect for an intermittent and for a poor
connection on the APP sensor circuit at the
harness connector of the ECM (pin 47 of C-56
connector).
4. Repair the connection(s) as necessary.
Did you find and correct the condition?
13 Replace APP sensor. Refer to Accelerator Pedal
Position (APP) Sensor Replacement in this section.
Did you complete the replacement?
14 Important: Replacement
programmed.
Replace the ECM. Refer to Engine Control Module
(ECM) Replacement in this section.
Did you complete the replacement?
Action
ECM must
Value(s)
5.5 volts
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be
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Yes
Go to Step 7 Go to Step 10
Go to Step 15 Go to Step 14
Go to Step 15 Go to Step 12
Go to Step 15 Go to Step 14
Go to Step 15 Go to Step 14
Go to Step 15 Go to Step 13
Go to Step 15 Go to Step 14
Go to Step 15
Go to Step 15
No
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