Diagnostic procedure

2006 Mazda 6 i, 4D Sedan, AutomaticSECTION Diagnostic procedure
DIAGNOSTIC PROCEDURE

STEP INSPECTION ACTION
1 Connect WDS or equivalent to DLC-2.
Do the following conditions appear?
  • Engine is not completely started.
  • DTC B1681 is displayed.
Yes Both conditions appear: 
Go to Step 3.
No Either or other condition appears: 
Go to the next step.
2 Does engine stall after approx. 2 seconds  since engine is started? Yes Go to the next step.
No Immobilizer system is okay.
Go to Step 10.
3 Is coil connector securely connected to coil? Yes Go to the next step.
No Connect coil connector securely.
Return to Step 2.
4 Does security light illuminate? Yes Go to the next step.
No Inspect instrument cluster and wiring harness.
5 Connect WDS or equivalent to DLC-2 and retrieve DTC.
Are any of the following DTCs displayed?
DTC 
B1213, B1342, B1600, B1602, B1681, B2103, B2431 
Yes Go to appropriate DTC test.
No Go to the next step.
6 Is there continuity between PCM GND terminals 1AZ, 1BB, 1BD, 1BH and GND? Yes Go to the next step.
No Repair or replace wiring harness.
7 Measure voltage between PCM GND terminals 1AZ, 1BB, 1BD, 1BH and coil terminal C.
Is voltage below 1.0 V  ?
Yes Go to the next step.
No Repair or replace wiring harness.
8 Turn ignition switch to ON position.
Access VPWR PID.
Is VPWR PID normal?
VPWR PID 
Battery voltage 
Yes Go to the next step.
No Repair or replace wiring harness.
9 Disconnect coil connector.
Turn ignition switch to ON position.
Is there battery voltage at coil connector terminal D?
Yes Inspect for the following:
  • Open or short circuit between coil terminal A and PCM terminal 1F.
  • Open or short circuit between coil terminal B and PCM terminal 1E.
No Repair or replace wiring harness between coil connector terminal D and fuse panel.
10 Verify the following:
  • Vacuum connection
  • Air cleaner element
  • No air leakage from intake-air system
  • No restriction of intake-air system
  • Proper sealing of intake manifold and components attached to intake manifold: EGR valve
  • Ignition wiring
  • Fuel quality: proper octane, contamination, winter/summer blend
  • Electrical connections
  • Smooth operation of throttle valve

Are all items normal?
Yes Go to the next step.
No Service if necessary.
Repeat Step 10.
11 Turn ignition switch to OFF position.
Disconnect TP sensor connector.
Measure voltage at TP sensor connector terminal B with ignition switch ON.
Voltage 
4.5-5.5 V 
Is voltage normal?
Yes Go to the next step.
No Inspect and repair open or short circuit between PCM terminal 2AO and TP sensor terminal B.
12 Turn ignition switch to OFF position.
Disconnect accelerator position sensor connector.
Measure voltage at accelerator position sensor connector VREF terminals with ignition switch to ON position.
Voltage 
4.5-5.5 V 
Is voltage normal?
Yes Go to the next step.
No Inspect and repair open or short circuit for the following:
  • PCM terminal 1AJ and accelerator position sensor terminal A
  • PCM terminal 1AL and accelerator position sensor terminal D
13 Connect WDS or equivalent to DLC-2.
Turn ignition switch to ON position (Engine off).
Retrieve any DTCs.
Are there any DTCs displayed?
Yes DTC is displayed: 
Go to appropriate DTC test.
Communication error message is displayed: 
Inspect for the following:
  • Open circuit between main relay and PCM terminal 1BE or 1AW(1)
  • Open main relay terminal E and PCM terminal 1Q
  • Main relay is stuck open.
  • Open or poor GND circuit (PCM terminal 1AZ, 1BB, 1BD or 1BH)
  • Poor connection of vehicle body GND
No No DTC is displayed: 
Go to the next step.
14 Start engine at part throttle.
Does engine run smoothly at part throttle?
Yes Inspect electronic throttle control system operation.
(See ELECTRONIC THROTTLE CONTROL SYSTEM INSPECTION ).
No Go to the next step.
15 Connect WDS or equivalent to DLC-2.
Access RPM PID.
Is RPM PID indicating engine speed during engine cranking?
Yes Go to the next step.
No Inspect for the following:
  • Open or short circuit in CKP sensor
  • Open or short circuit between CKP sensor and PCM terminal 2W or 2AQ
  • Open or short circuit in between CKP sensor and GND
  • Open or short circuit in CKP sensor harnesses

If CKP sensor and harness are okay, go to the next step.
16 Visually inspect CKP sensor and teeth of crankshaft pulley.
Are CKP sensor and teeth of crankshaft pulley normal?
Yes Go to the next step.
No Replace malfunctioning parts.
17 Inspect ignition coil related harnesses condition (intermittent open or short circuit) for all cylinders.
Are all harnesses condition normal?
Yes Go to the next step.
No Repair suspected wiring harness.
18 Perform Spark Test.
(See SPARK TEST ).
Is the strong blue spark visible at each cylinder?
Yes Go to the next step.
  • If symptom occurs with A/C on, go to Step 23.
No Repair or replace malfunctioning part according to spark test results.
19 Inspect spark plug condition.
Is spark plug wet, covered with carbon or grayish white?
Yes Spark plug is wet or covered with carbon: 
Inspect for fuel leakage from injector.
Spark plug is grayish white: 
Inspect for clogged fuel injector.
No Install spark plugs on original cylinders.
Go to the next step.
20 Remove and shake PCV valve.
Does PCV valve rattle?
Yes Go to the next step.
No Replace PCV valve.
21 Inspect for restriction in the exhaust system.
Is there any restriction?
Yes Inspect exhaust system.
No Go to the next step.
22 Install fuel pressure gauge between fuel pipe and fuel distributor.
Short check connector terminal F/P to body GND using a jumper wire.
Turn ignition switch to ON position.
Is fuel line pressure correct with ignition switch ON?
(See FUEL LINE PRESSURE INSPECTION ).
Yes Go to the next step.
No Zero or low: 
Inspect fuel pump relay and fuel pump circuit.
Inspect for clogged fuel line.
If okay, replace fuel pump unit.
High: 
Replace fuel pump unit.
23 Visually inspect for fuel leakage at fuel injector O-ring and fuel line. Service if necessary.
Is fuel line pressure held after ignition switch is turned off?
(See FUEL LINE PRESSURE INSPECTION ).
Yes Go to the next step.
No Inspect fuel injector.
If fuel injector is okay, replace fuel pump unit.
24
NOTE:
  • The following test is for stall concerns with A/C on. If other symptoms exist, go to the next step.
Connect pressure gauges to A/C low and high pressure side lines.Turn A/C on and measure low side and high side pressures.Are pressures within specifications?(See REFRIGERANT PRESSURE CHECK [L3, AJ] ).
Yes Go to the next step.
No If A/C is always on, go to symptom troubleshooting "NO. 24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY ".
For other symptoms, inspect the following:
  • Refrigerant charging amount
  • Condenser fan operation
25 Disconnect vacuum hose between purge solenoid valve and intake manifold from purge solenoid side.
Plug opening end of vacuum hose.
Start engine.
Is engine stall now eliminated?
Yes Inspect if purge solenoid valve sticks open.
Inspect EVAP control system.
No Go to the next step.
26 Is air leakage felt or heard at intake-air system components while racing engine to higher speed? Yes Repair or replace.
No Go to the next step.
27 Inspect engine condition while tapping EGR valve housing.
Does engine condition improve?
Yes Replace EGR valve.
No Go to the next step.
28 Inspect variable valve timing control system operation.
(See VARIABLE VALVE TIMING CONTROL SYSTEM OPERATION INSPECTION ).
Does variable valve timing control work properly?
Yes Go to the next step.
No Repair or replace malfunctioning parts according to variable valve timing control system operation inspection results.
29 Is engine compression correct? Yes Inspect valve timing.
No Inspect for cause.
30 Verify test results.
  • If okay, return to diagnostic index to service any additional symptoms.
  • If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis.
    • If vehicle is repaired, troubleshooting completed.
    • If vehicle is not repaired or additional diagnostic information is not available, reprogram PCM if later calibration is available. Retest.
(1) California emission regulation applicable ATX model
RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.