1991 Mazda Truck B Series Truck |
Test Connector
When problems occur in ECU monitored input or output devices, test the system to find the cause. During testing, failures of input and output devices are retrieved from the ECU as malfunction code numbers and displayed on the dash mounted malfunction indicator light (MIL).
| NOTE: | The ECU constantly checks for input device malfunctions. However, it only checks for output device malfunctions in a 3 second period after the ignition switch is turned “ON” with test connector grounded. If there is more than one malfunction code present, the lowest number code is displayed first, followed by subsequent codes in numerical order. This procedure is only applicable to vehicles with an MIL system that will display codes. |
INSPECTION PROCEDURE
- Warm up engine to normal operating temperature and turn ignition “OFF.”
- Ground test connector (Green: 1-pin) with a jumper wire.
| NOTE: | Test connector is located next to self-diagnostic connector. |
- Turn ignition switch “ON.”
- If MIL illuminates, goes off, and stays off, no codes are present.
- If MIL illuminates, goes off, and then starts flashing, codes are present.
- Start engine and check for additional codes.
- If any codes are retrieved, refer to Malfunction Code Charts under DIAGNOSTIC CHARTS. Repair as required.
AFTER-REPAIR PROCEDURE
- Erase ECU malfunction code memory by disconnecting the negative battery cable and depressing the brake pedal for at least five seconds. Reconnect battery cable.
- Ensure engine is at normal operating temperature. Ground test connector.
- Turn ignition switch “ON.”
- If MIL illuminates, goes off, and stays off, no codes are present.
- If MIL illuminates, goes off, and then starts flashing, codes are present.
- Start the engine and check for additional codes.
- If any codes are retrieved, repair problem and repeat after-repair procedure.
Diagnostic codes
| 1 | No1 Ign Pulse |
| 9 | Water Thermo Sensor |
| 13 | Vacuum Sensor |
| 14 | Atmospheric Pressure Sensor |
| 15 | Oxygen Sensor |
| 16 | EGR Position Sensor |
| 17 | Feedback System |
| 18 | A/F Solenoid Valve |
| 22 | Slow Fuel Cut Solenoid |
| 23 | Coasting Richer Solenoid or Circuit |
| 26 | Purge Solenoid Valve or Circuit |
| 28 | Duty Solenoid Vacuum Valve or Circuit |
| 29 | Duty Solenoid Vent Valve or Circuit |
| 30 | ACV Solenoid Valve or Circuit |
| 34 | Idle-Up Solenoid Valve (for A/C) or Circuit |
| 35 | Idle-Up Solenoid Valve (for A/T) or Circuit |
| 45 | Vacuum Solenoid Valve or Circuit |