Diagnostic Procedures
WARNING: This page is about a different car, the 2002 Mazda B4000, 2002 Mazda B3000, and 2002 Mazda B2300. However, it is still accessible from the selected car via links, so may be relevant.
- If QUICK TEST was not performed, go to QUICK TEST
under SELF-DIAGNOSTIC SYSTEM. If QUICK TEST was performed, go to next step.NOTE: If this DTC was set by an intermittent condition, maximum benefit will be obtained by having another technician wiggle harness and connectors when making measurements.
- P0403: Check Connection Of EEGR To Harness
Check EEGR harness connector. If connector is properly seated, go to next step. If connector is not properly seated, firmly seat connector. Go to step 11 . - Check For B+ At Harness Connector To EEGR Motor
With KOEO, disconnect EEGR connector. Measure voltage between VPWR circuit (Light Blue/Orange wire) at EEGR harness connector and battery negative terminal. See Fig 1 . If voltage is more than 10.5 volts, go to next step. If voltage is 10.5 volts or less, repair open supply circuit. See WIRING DIAGRAMS article. Go to step 11 . - Check EEGR Harness Circuit For Shorts To Ground
Turn ignition off. Disconnect PCM connector. Install breakout box, leaving PCM disconnected. Measure resistance between the following breakout box terminals and battery ground:- Breakout box terminal No. 73 (EGRM1 circuit).
- Breakout box terminal No. 99 (EGRM2 circuit).
- Breakout box terminal No. 72 (EGRM3 circuit).
- Breakout box terminal No. 98 (EGRM4 circuit).
If each resistance reading is more than 10,000 ohms, go to next step. If any resistance reading is 10,000 ohms or less, repair short to ground in wiring harness. See WIRING DIAGRAMS article. Go to step 11 .
- Check For Open Circuits In EEGR Harness
Measure resistance of each EEGR circuit between the following breakout box terminals and EEGR harness connector:- Breakout box terminal No. 73 (EGRM1 circuit) and EEGR harness connector (Violet/Orange wire).
- Breakout box terminal No. 99 (EGRM2 circuit) and EEGR harness connector (Orange/Green wire).
- Breakout box terminal No. 72 (EGRM3 circuit) and EEGR harness connector (Gray/Red wire).
- Breakout box terminal No. 98 (EGRM4 circuit) and EEGR harness connector (Tan/Red wire).
If each resistance reading is more than 10,000 ohms, go to next step. If any resistance reading is 10,000 ohms or less, repair short to ground in wiring harness. See WIRING DIAGRAMS article. Go to step 11 .
- Check EEGR Harness Circuits For Shorts To Each Other
Measure resistance between each EEGR circuit by measuring breakout box terminal No. 72 and breakout box terminals No. 73, 98 and 99. Record readings. Measure resistance between each EEGR circuit by measuring breakout box terminal No. 73 and breakout box terminals No. 98 and 99. Record readings. Measure resistance between each EEGR circuit by measuring breakout box terminals No. 98 and 99. Record reading. If each resistance is more than 10,000 ohms, go to next step. If any resistance reading is 10,000 or less, repair short in wiring harness. See WIRING DIAGRAMS article. Go to step 11 . - Check For Shorts To Power In EEGR Harness
Remove breakout box. Reconnect PCM connector. With KOEO, measure voltage between each EEGR circuit at EEGR connector and battery negative terminal. See Fig 1 . If voltage is less than 0.1 volt, go to next step. If voltage is 0.1 volt or more, repair short to power in wiring harness. See WIRING DIAGRAMS article. Go to step 11 . - Check EEGR Motor Windings For Open & Short Circuits
Turn ignition off. Disconnect PCM connector. Reconnect EEGR connector. Install breakout box, leaving PCM disconnected. Measure resistance between breakout box terminals No. 71 and/or 97, and the following breakout box terminals:- Breakout box terminal No. 73 (EGRM1 circuit).
- Breakout box terminal No. 99 (EGRM2 circuit).
- Breakout box terminal No. 72 (EGRM3 circuit).
- Breakout box terminal No. 98 (EGRM4 circuit).
If each resistance reading is 20-24 ohms, go to next step. If any resistance reading is not 20-24 ohms, replace faulty EEGR assembly. Go to step 11 .
- Check EEGR Motor Windings For Shorts To Ground
Turn ignition off. Measure resistance between the following breakout box terminals and battery negative terminal:- Breakout box terminal No. 73 (EGRM1 circuit).
- Breakout box terminal No. 99 (EGRM2 circuit).
- Breakout box terminal No. 72 (EGRM3 circuit).
- Breakout box terminal No. 98 (EGRM4 circuit).
If each resistance reading is more than 10,000 ohms, replace faulty PCM. Go to step 11 . If any resistance reading is 10,000 ohms or less, replace faulty EEGR assembly. Go to step 11 .
NOTE: If DTCs P0102, P0103, P0107, P0108, P1100 or P1101 is also set, repair these DTCs before continuing with this test procedure.NOTE: During next test step, engine speed must be held constant. Performing next test step may generate additional DTCs. After performing next test step, clear any DTCs which may have set. - DTC P0400/P1408: Check For Stuck EGR Valve Operation
Disconnect PCM connector. Install breakout box, leaving PCM connected to breakout box. With KOER, select Diagnostic Data Link. Select PCM. Select Active Command Modes. Select Output Test Mode - Bench Test. Using scan tool, access EEGR PID (EGRMC) and MAP PID (MAP) (if available). Operate engine at normal operating temperature with engine speed 1000-1200 RPM (to prevent stalling). Add a small amount of EGR (approximately 8-12 steps) by pressing trigger (with EGRMC high-lighted). Using rotary dial while monitoring MAP PID or voltage at breakout box terminal No. 63 (MAP circuit). MAP value should increase as EGR is introduced. If an increase in MAP value is observed, condition is not present at this time. Make sure MAP is properly seated and vacuum source is not blocked. Go to next step. If no increase in MAP value is observed, replace faulty EEGR assembly. Go to next step. - Verify Trouble Shooting Of DTCs Completed
Perform QUICK TEST under SELF-DIAGNOSTIC SYSTEM. If any DTC is present, go to applicable procedure for other DTCs. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no DTCs are set, trouble shooting is complete.