Isuzu 1999 RODEO Workshop Manual page 710

Circuit Description
The electronic ignition system uses a dual coil method of
spark distribution. In this type of ignition system, the
powertrain control module (PCM) triggers the correct
driver inside the ignition control module (ICM), which then
triggers the correct ignition coil based on the 58X signal
received from the crankshaft position sensor (CKP). The
spark plug connected to the coil fires when the ICM opens
the ground circuit for the coil's primary circuit.
During crank, the PCM monitors the CKP 58X signal. The
CKP signal is used to determine which cylinder will fire
first. After the CKP 58X signal has been processed by the
PCM, it will command all four injectors to allow a priming
shot of fuel for all the cylinders. After the priming, the
injectors are left OFF during the next four 58X reference
pulses from the CKP. This allows each cylinder a chance
to use the fuel from the priming shot. During this waiting
period, a camshaft position (CMP) signal pulse will have
been received by the PCM. The CMP signal allows the
PCM to operate the injectors sequentially based on
camshaft position. If the camshaft position signal is not
Step
1 Was the "On–Board Diagnostic (OBD) System Check"
performed?
2 Use the Tech 2 and check for any DTC's.
Are any DTC's stored?
3 Check the 15A ignition coil fuse, the 15A engine device
fuse, and the 15A ECM fuse.
Was a fuse blown?
4 Check for a short to ground and replace the fuse.
Is the action complete?
5 1. Ignition ON.
2. Use a grounded test lamp to verify that B+ is
available at the ignition coil fuse, the engine device
fuse, and the ECM fuse.
Was B+ available at the fuses?
6 Repair the open ignition feed circuit.
7 1. Disconnect the ignition secondary wire at the No.1.
2. Install a spark tester J 26792 at the end of the
disconnected ignition coil.
3. Clip the spark tester J 26792 to a good ground (not
near the battery).
4. Observe the spark tester while the engine is
cranking.
Was a crisp blue spark observed? (Only one or two
sparks followed by no result is considered the same as
"No Spark.")
RODEO X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION
Engine Cranks But Will Not Run
Action
present at start–up, the PCM will begin sequential fuel
delivery with a 1–in–4 chance that fuel delivery is correct.
The engine will run without a CMP signal, but will set a
DTC code.
Diagnostic Aids
An intermittent problem may be caused by a poor
connection, rubbed–through wire insulation or a wire
broken inside the insulation. Check for the following
items:
f Poor connection or damaged harness – Inspect the
PCM harness and connectors for improper mating,
broken locks, improperly formed or damaged
terminals, poor terminal–to–wire connection, and
damaged harness.
f Faulty engine coolant temperature sensor – Using a
Tech 2, compare engine coolant temperature with
intake air temperature on a completely cool engine.
Engine coolant temperature should be within 10°C of
intake air temperature. If not, replace the ECT sensor.
Value(s)
— Go to Step 2
Applicable
— DTC Table
— Go to Step 4
— Verify repair
— Go to Step 7
Go to Fuel
Electrical Test
—
Go to Step 16
—
6E1–83
Yes No
Go to OBD
System
Check
Go to
Go to Step 3
Go to Step 5
—
Go to Step 6
Go to Fuel
System
System
Diagnosis
Go to Step 8