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Home >> Mazda >> 2002 >> Tribute LX, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 27 (Engine Controls - Self-Diagnostics - 2.5L) >> Diagnostic Tests >> DTC P0300, P0301, P0302, P0303, P0304, P0305, P0306 Or P0316: Misfire Detection Monitor >> Diagnosis & Repair Procedure

Diagnosis & Repair Procedure

WARNING: This page is about a different car, the 2002 Mazda 626. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ensure FREEZE FRAME DATA has been recorded. Check for related service bulletins. Repair as necessary and go to next step.
  2. If vehicle runs out of fuel, a trouble code may be stored in PCM memory. Ensure vehicle has not recently run out of fuel. If vehicle has run out of fuel, system is okay at this time. Go to step  15 . If not, go to next step.
  3. Using scan tool, check for CMP sensor, ignition coil primary circuit Knock Sensor (KS) DTCs or any other DTC that may cause a misfire. If any other DTCs are present, go to appropriate test and repair first. If no other DTCs are present, check secondary spark plug wires for high resistance, corrosion or damage. Repair or replace as necessary. If wires are okay, go to next step.
  4. Perform KOER test. If no KOER DTCs are present, go to next step. If KOER DTC P1131 or P1151 is present, go to next step. If any other DTCs are present, proceed to appropriate DTC.
  5. Turn ignition off. Disconnect PCM connector. Check for loose, damaged or corroded connector terminals. Repair as necessary. Measure resistance between PCM harness connector terminals No. 71 (Red/Black wire) and No. 97 (Red/Black wire) and PCM harness connector terminals corresponding to appropriate fuel injector circuit. See Figure . See FUEL INJECTOR CIRCUIT IDENTIFICATION  table. Resistance should be 12-16 ohms. If resistance is not as specified, go to step  15 . If resistance is as specified, go to next step.
  6. Backprobing, connect non-powered, 12-volt test light between PCM harness connector terminals No. 71 (Red/Black wire) or No. 97 (Red/Black wire), and PCM harness connector terminals corresponding to appropriate fuel injector circuit. See FUEL INJECTOR CIRCUIT IDENTIFICATION  table. Start engine. If test light glows dimly, system is functioning properly. Reconnect all components and go to next step. If test light does not glow dimly (no light/bright light), go to step  15 .
  7. Turn ignition off. Release fuel pressure. See FUEL PRESSURE RELEASE under FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES article. Install fuel pressure gauge. Start engine and allow it to idle. Record fuel pressure gauge reading. Increase engine speed to 2500 RPM and maintain for one minute. If fuel pressure is 37-46 psi (2.1-3.1 kg/cm2 ) during both engine speeds, go to step  15 . If fuel pressure is not 37-46 psi (2.1-3.1 kg/cm2 ) during both engine speeds, go to next step.
  8. With engine at idle, record fuel pressure gauge reading. Increase engine speed to 2500 RPM and maintain for one minute. Check for fuel leaking from around fuel injectors, fuel pressure regulator and fuel hoses. Repair if necessary. Turn ignition off. Turn ignition on and record fuel pressure gauge reading. If fuel pressure remains within 21 psi (1.5 kg/cm2 ) of reading taken at idle for 60 seconds, go to next step. If fuel pressure does not remain within 21 psi (1.5 kg/cm2 ) of reading taken at idle for 60 seconds, check for fuel leaks.
  9. Turn ignition off. Use appropriate fuel injector tester to flow test fuel injectors. See SYSTEM & COMPONENT TESTING - MIATA, MILLENIA, MPV, PROTEGE, PROTEGE5 & 626 article. Follow injector tester instructions. If fuel injector flow or leakage rate is not okay, replace or clean defective fuel injector(s) and go to step  15 . If flow rate for each fuel injector is okay, fuel delivery system is okay, go to next step.
  10. Inspect all vacuum hoses for kinks or damage. Ensure all vacuum connections are clean and tight. Repair or replace as necessary and go to step  14 . If vacuum system is okay, go to next step.
  11. Inspect carbon canister. Replace carbon canister if it contains liquid fuel and go to step  15 . If carbon canister is okay, go to next step.
  12. Inspect vacuum hoses between engine vacuum port and carbon canister for restrictions or damage. Ensure all vacuum connections are clean and tight. Check fuel tank vent system for restrictions. Repair or replace as necessary and go to step  15 . If vacuum hoses and fuel tank vent system are okay, go to next step.
  13. Check purge solenoid valve for proper operation. See SYSTEM & COMPONENT TESTING - MIATA, MILLENIA, MPV, PROTEGE, PROTEGE5 & 626 article. Replace as necessary and go to step  15 . If purge solenoid valve is okay, go to next step.
  14. Check engine compression. Ensure engine compression is even and within specification. Check PCV system for restrictions or leaks. Repair or replace as necessary and go to next step. If no faults can be found, go to next step.
  15. Reconnect all connections. Turn ignition on. Clear DTCs. See CLEARING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. Start engine. Using scan tool, perform OBD II drive mode. See DRIVE MODES  under SELF-DIAGNOSTIC SYSTEM. Using scan tool, access DIAGNOSIS MONITORING TEST RESULTS. Monitor TEST #10:50:00 (number of total misfires), #10:53:01 (misfire rate per 200 engine revs), #10:53:02 (misfire rate per 200 engine revs), #10:53:03 (misfire rate per 200 engine revs), #10:53:04 (misfire rate per 200 engine revs), #10:53:05 (misfire rate per 200 engine revs), #10:53:06 (misfire rate per 200 engine revs), #10:54:00 (highest misfire rate per 200 engine revs), #10:55:00 (highest misfire rate per 1000 engine revs) and #10:56:00 (total number of ignition during monitoring). If measured value is within specification, replace PCM and go to next step. See REMOVAL, OVERHAUL & INSTALLATION article. On vehicles equipped with immobilizer system, reprogram ignition key identification numbers. See COMPUTER RELEARN PROCEDURES - IMPORT article in GENERAL INFORMATION. If measured value is not within specification, go to next step.
  16. Perform DTC confirmation procedure. See DTC CONFIRMATION PROCEDURE  under SELF-DIAGNOSTIC SYSTEM. Check for DTCs. See RETRIEVING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. If any other DTC is present, go to appropriate test.
FUEL INJECTOR CIRCUIT IDENTIFICATION

Injector No. Terminal No.
1 75 (Blue wire)
2 101 (Blue/White wire)
3 74 (Blue/Red wire)
4 100 (Violet wire)
5 73 (White wire)
6 99 (Yellow/Violet wire)
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