Mazda MX-6 1998, Workshop Manual, Page: 363 / 1282

TROUBLESHOOTING [ENGINE CONTROL KL]
STEP INSPECTION ACTION
2
Retrieve and record any continuous memory,
KOEO and KOER DTCs.
Are there any DTCs displayed?
Yes Diagnostic trouble code displayed.
Go to appropriate DTC test.
No Go to next step.
3
Is any other drivability concern present? Yes Go to appropriate flow chart.
No
Go to next step.
4 Connect NGS tester to DLC.
Access ECT PID.
Warm-up engine and run it at idle.
Verify ECT PID is correct.
• ECT PID
¡y 0 1 -40B ENGINE COOLANT
TEMPERATURE SENSOR
INSPECTION [KL]
Is ECT PID correct?
Yes Go to next step.
No Check cooling system.
5
Is strong blue spark visible at each
disconnected high-tension lead while cranking
engine?
Yes Check following:
• Spark plug(s) malfunction.
• CMP sensor improperly installated.
• Damage of trigger wheel on camshaft.
• Open or short circuit on CMP sensor.
• Open or short circuit between CMP sensor and PCM.
Repair or replace malfunctioning part.
If okay, go to next step.
No Check following:
• Hightension leads.
• Ignition coil and connector.
6
Install fuel pressure gauge between fuel filter
and fuel distributor.
Start engine and run it at idle.
Measure fuel line pressure at idle.
Is fuel line pressure correct at idle?
Fuel lin e pre ssu re
210— 260 kPa
{2.1— 2.6 kgf/cm2, 30— 37 psi>
Yes Go to next step.
No Z ero o r low:
Check fuel pump circuit.
Check for open fuel pump relief valve.
Check for fuel leak inside pressure regulator.
Check for clogged main fuel line.
High:
Check pressure regulator for high pressure cause.
Check for clogged fuel return line.
7 Does fuel line pressure remain at specification
for 60 seconds when ignition switch is turned
ON?
Fuel line pressure
210— 260 kPa
(2.1— 2.6 kgf/cm2, 30— 37 psi}
Yes Go to next step.
No
Check pressure regulator for high pressure cause.
8 Remove and shake PCV valve.
Does PCV valve rattle?
Yes Go to next step.
No Replace PCV valve.
9
Check for fuel saturation inside charcoal
canister.
Is excess amount of liquid fuel present in
canister?
Yes Replace charcoal canister.
No Check fuel tank vent system.
Go to next step.
10
Is there restriction in exhaust system? Yes Check exhaust system.
No Go to next step.
11 Check engine condition while tapping EGR
valve housing. Does engine condition
improve?
Yes Replace EGR valve.
No Go to next step.
12
Verify test results. If okay, return to diagnostic index to service any additional symptoms.
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