2005 SUZUKI JIMNY ecm

Downloaded from www.Manualslib.com manuals search engine 6F-2 IGNITION SYSTEM (ELECTRONIC IGNITION SYSTEM)
General Description
The ignition system is an electronic (distributorless) ignition system. It consists of the parts as described below
and has an electronic ignition control system.
ECM
It detects the engine and vehicle conditions through the signals from the sensors, determines the most suit-
able ignition timing and time for electricity to flow to the primary coil and sends a signal to the ignitor (power
unit) in the ignition coil assembly.
Ignition coil assembly (including an ignitor)
The ignition coil assembly has a built-in ignitor which turns ON and OFF the current flow to the primary coil
according to the signal from ECM. When the current flow to the primary coil is turned OFF, a high voltage is
induced in the secondary coil.
High tension cords and spark plugs.
CMP sensor (Camshaft position sensor) and CKP sensor (Crankshaft position sensor)
Using signals from these sensors, ECM identifies the specific cylinder whose piston is in the compression
stroke, detects the crank angle and adjust initial ignition timing automatically.
TP sensor, ECT sensor, MAP sensor and other sensors/switches
Refer to “Electronic Control System” in Section 6E for details.
Although this ignition system does not have a distributor, it has two ignition coil assemblies (one is for No.1 and
No.4 spark plugs and the other is for No.2 and No.3 spark plugs). When an ignition signal is sent from ECM to
the ignitor in the ignition coil assembly for No.1 and No.4 spark plugs, a high voltage is induced in the secondary
coil and that passes through the high-tension cords and causes No.1 and No.4 spark plugs to spark simulta-
neously. Likewise, when an ignition signal is sent to the ignitor in the other ignition coil assembly, No.2 and No.3
spark plugs spark simultaneously.
SYSTEM COMPONENTS
1. ECM 7. ECT sensor 13. Monitor connector
2. Ignition coil assembly for No.1 and No.4 spark plugs 8. IAT sensor 14. Knock sensor
3. Ignition coil assembly for No.2 and No.3 spark plugs 9. TP sensor 15. DLC
4. CMP sensor 10. VSS 16. Spark plugs
5. CKP sensor 11. Transmission range switch (A/T)
6. MAP sensor 12. High-tension cords

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SYSTEM WIRING DIAGRAM
Diagnosis
1. Ignition switch 7. No.1 spark plug
2. Main relay 8. No.2 spark plug
3. Ignition coil assembly for No.1 and No.4 spark plugs 9. No.3 spark plug
4. Ignition coil assembly for No.2 and No.3 spark plugs 10. No.4 spark plug
5. CMP sensor 11. Sensed information (MAP sensor, ECT sensor, IAT sensor, TP sensor, Knock sensor, VSS, Park/
Neutral position signal, Electric load signal, Engine start signal, Test switch terminal)
6. CKP sensor
Condition Possible Cause Correction
Engine cranks, but will
not start or hard to
start (No spark)Blown fuse for ignition coil Replace.
Loose connection or disconnection of lead wire
or high-tension cord(s)Connect securely.
Faulty high-tension cord(s) Replace.
Faulty spark plug(s) Adjust, clean or replace.
Faulty ignition coil Replace ignition coil assembly.
Faulty CKP sensor or CKP sensor plate Clean, tighten or replace.
Faulty ECM Replace.
Poor fuel economy or
engine performanceIncorrect ignition timing Check related sensors and CKP
sensor plate.
Faulty spark plug(s) or high-tension cord(s) Adjust, clean or replace.
Faulty ignition coil assembly Replace.
Faulty CKP sensor or CKP sensor plate Clean, tighten or replace.
Faulty ECM Replace.

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IGNITION SYSTEM DIAGNOSTIC FLOW TABLE
Step Action Yes No
1Was “Engine Diagnostic Flow Table” in Section 6 per-
formed?Go to Step 2. Go to “Engine Diag.
Flow Table” in Section
6.
2Ignition Spark Test
1) Check all spark plugs for condition and type refer-
ring to “Spark Plugs” section.
2) If OK, perform ignition spark test, referring to “Igni-
tion Spark Test” section.
Is spark emitted from all spark plugs?Go to Step 11. Go to Step 3.
3Diagnostic Trouble Code (DTC) Check
Is DTC stored in ECM?Go to applicable DTC
Diag. Flow Table in
Section 6.Go to Step 4.
4Electrical Connection Check
1) Check ignition coil assemblies and high-tension
cords for electrical connection.
Are they connected securely?Go to Step 5. Connect securely.
5High-tension Cords Check
1) Check high-tension cord for resistance referring to
“High-Tension Cords” section.
Is check result satisfactory?Go to Step 6. Replace high-tension
cord(s).
6Ignition Coil Assembly Power Supply and Ground Cir-
cuit Check
1) Check ignition coil assembly power supply and
ground circuits for open and short.
Are circuits in good condition?Go to Step 7. Repair or replace.
7Ignition Coil Assembly Check
1) Check ignition coil for resistance referring to “Igni-
tion Coil Assembly” section.
Is check result satisfactory?Go to Step 8. Replace ignition coil
assembly.
8Crankshaft Position (CKP) Sensor Check
1) Check crankshaft position sensor referring to Step
2 and 6 of “DTC P0335 (No.23) CKP Sensor Cir-
cuit Malfunction” in Section 6.
Is check result satisfactory?Go to Step 9. Tighten CKP sensor
bolt, replace CKP sen-
sor or CKP sensor
plate.
9Ignition Trigger Signal Circuit Check
1) Check ignition trigger signal wire for open, short
and poor connection.
Is circuit in good condition?Go to Step 10. Repair or replace.
10A Known-good Ignition Coil Assembly Substitution
1) Substitute a known-good ignition coil assembly
and then repeat Step 2.
Is check result of Step 2 satisfactory?Go to Step 11. Substitute a known-
good ECM and then
repeat Step 2.
11Ignition Timing Check
1) Check initial ignition timing and ignition timing
advance referring to “Ignition Timing” section.
Is check result satisfactory?System is in good con-
dition.Check CKP sensor,
CKP sensor plate and
input signals related to
this system.

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5) Fix ignition timing to initial one as follows.
a) When using SUZUKI scan tool:
Select “MISC” mode on SUZUKI scan tool and fix ignition
timing to initial one.
b) Without using SUZUKI scan tool: (vehicle without immobi-
lizer indicator lamp)
Disconnect scan tool from DLC, and connect D and E ter-
minals of monitor connector (1) or E to body ground by
using service wire so that ignition timing is fixed on initial
one.
6) Using timing light (1), check that ignition timing is within
specification.
Initial ignition timing (test switch terminal grounded or
fixed with SUZUKI scan tool)
5
± 3° BTDC at idle speed
Ignition order
1-3-4-2
7) If ignition timing is out of specification, check the followings:
CKP sensor
CKP sensor plate
TP sensor
Test switch signal circuit
VSS
Timing chain cover installation
8) After checking Initial Ignition Timing, release ignition timing
fixation by using SUZUKI scan tool or disconnect service
wire from monitor connector.
9) With engine idling (test switch terminal ungrounded, throttle
opening at closed position and car stopped), check that igni-
tion timing is about 7°–17° BTDC. (Constant variation within
a few degrees from 7°–17° indicates no abnormality but
proves operation of electronic timing control system.) Also,
check that increasing engine speed advances ignition timing.
If above check results are not satisfactory, check CKP sen-
sor, test switch terminal circuit and ECM.