Engine Controls - Spark Knock/Surge/High Idle
01-014/052004-2005 B4000 - SPARK KNOCK DURING
ACCEL, SURGE AT CRUISE (35-50 MPH), HIGH IDLE
BETWEEN SHIFTS OR IN NEUTRAL (MT ONLY)
APPLICABLE MODEL(S)/VINS
2004-2005 B4000
DESCRIPTION
Some B4000 vehicles may experience one or more of the following concerns:
^ Spark knock during acceleration between 1800-2400 RPM.
^ Surge during cruise at steady speeds between 35-50 MPH (56-80 Km/h). The condition will occur afier a cold start and may continue for approximately 5 miles (8 Km) or 5 minutes.
^ Higher than expected idle between shifts, during a coast down with the clutch depressed, or with the transmission in neutral (manual transmission vehicles only).
These concerns may be caused by incorrect logic of the PCM's software.
Customers having any of these concerns should have their vehicle repaired using the following repair procedure.
REPAIR PROCEDURE
1. Verify customer concern.
2. Reboot the WDS PTU to clear memory before reprogramming.
3. Using WDS B35.9 or later software, reprogram the PCM to the latest calibration (refer to "Calibration Information" table) by following the "Module Reprogramming" procedure.
NOTE:
^ Always update the WDS PTU first,then install the needed calibration file that WDS shows during PCM reprogramming. Go to "WDS Calibration" on ESI and download the "update" file. If the PTU is not updated to the latest WDS calibration level, the calibration file will not install into the PTU.
^ WDS shows the calibration part numbers afier programming the PCM.
^ Please be aware that PCM calibration part numbers and file names listed in any Service Bulletin may change due to future releases of WDS software, and additional revisions made to those calibrations for service related concerns.
^ When reprogramming a PCM, WDS will always display the "latest" calibration P/N available for that vehicle. If any calibration has been revised/updated to contain new information for a new service concern/issue, it will also contain all previously released calibrations.
^ When performing this procedure, if the WDS PTU is not docked and connected to 115V-120V, we recommend that a battery charger be installed on the vehicle battery and turned ON to a maximum charge of no more than 20 AMPS to keep the vehicle battery up to capacity. If you exceed 20 AMPS, it will damage the WDS PTU. Also the external battery power supply cable should be connected to the vehicle battery and the PTU.
^ If there is a communication error, attempt to communicate using a different scan tool such as a different WDS, NGS, NGS+ or VCM. If communication cannot be established with any scan tool, perform voltage drop of PCM power and ground circuits. Also check that VREF circuits.
^ Install an "Authorized Modification" label (P/N 9999-95-AMDC-97) with the new calibration information next to the Emission Control sticker on the radiator support. The "Authorized Modification" label will inform technicians of the PCM calibration change if future repairs are necessary.
4. After performing the PCM reprogramming procedure, verify the repair by starting the engine and making sure there are no MIL illumination or abnormal warning lights present.
NOTE:
^ If any DTCs should remain afier performing DTC erase, diagnose the DTCs according to the appropriate Troubleshooting section of the Workshop Manual.
^ After PCM reprogramming, it is no longer necessary to road test the vehicle to "relearn" KAM (Keep Alive Memory).
CALIBRATION INFORMATION
NOTE:
The PCM Calibration Part Numbers listed above are provided for PCM reprogramming purposes only. These are not necessarily the same Mazda part numbers used to order an actual PCM through the Mazda Parts System. It is not necessary to order a PCM as part of this repair procedure.
WARRANTY INFORMATION
NOTE:
^ This warranty information applies only to verified customer complaints on vehicles eligible for warranty repair. Refer to the SRT microfiche for warranty term information.
^ Additional diagnostic time cannot be claimed for this repair.
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