Diagnosis & Repair Procedure

WARNING: This page is about a different car, the 2002 Mazda Protege5 and 2002 Mazda Protege. However, it is still accessible from the selected car via links, so may be relevant.

Turn ignition off. Connect scan tool to DLC-2. Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 6.
Ensure no other DTC have been set at this time. If any other DTC has been set, repair that problem first. If no other DTCs are set, go to next step.
Turn off A/C and all electrical accessories. Remove cooling fan relay No. 1 located in main fuse block at left side of engine compartment. Using scan tool, check ECT PID data. Ensure ECT PID data reads 210°F (99°C). Connect fused jumper wire between cooling fan relay No. 1 harness connector terminals "C" and "D". See Fig 1. ECT PID data should indicate a continual decrease that stops at 176-183°F (80-84°C), indicating thermostat is closed. If ECT PID data is not as specified, remove jumper wire and go to next step. If ECT PID data is as specified, remove jumper wire and go to step 5.

Fig 1: Identifying Cooling Fan Relay No. 1 Terminals
Courtesy of MAZDA MOTORS CORP.
Remove coolant thermostat and ensure it is not stuck open. Replace as necessary and go to next step. If thermostat is okay, check Engine Coolant Temperature (ECT) sensor operation. See ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - MIATA, MILLENIA, MPV, PROTEGE & 626 article. Replace ECT sensor as necessary and go to next step.

NOTE: If workshop interior and outdoor temperature difference is significant, PCM might not operate thermostat monitor. In order for the PCM to operate thermostat monitor, manufacturer recommends allowing engine to cool with vehicle outside workshop.

Reconnect all connections. Allow engine to cool. Turn ignition switch on. Clear DTCs. See CLEARING DIAGNOSTIC TROUBLE CODES under SELF-DIAGNOSTIC SYSTEM. Using scan tool, check IAT PID data. IAT PID data should be more than 14°F (-10°C). Difference between ECT and IAT should be less than 6°C. If all PID data is as specified, go to next step. If any PID data is out of specification, cool down engine and repeat this step.

NOTE: This step requires driving vehicle. DO NOT use chassis roller for this test. Allow engine to cool with vehicle outside workshop. Test drive must performed with no more than 3 stops within a 5 minute drive period. Test period depends on engine coolant temperature at engine start. The warmer the engine coolant, the less time required for test. For example if engine coolant temperature is 14°F (-10°C), monitoring period is 38 minutes, but if engine coolant temperature is 86°F (30°C) monitoring period is 8 minutes.

Start engine. Turn off A/C and all electrical accessories. Using scan tool, access DIAGNOSIS MONITORING TEST RESULTS in GENERIC OBD II FUNCTIONS. Monitor TEST #10:32:00. Drive vehicle 25-62 MPH until TEST value changes. If measured value is more than minimum value, go to next step. If measured value is less than minimum value, replace PCM and go to next step. See COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. If measured value is more than minimum value, go to next step.
Cycle ignition switch from off to on. Check for DTCs. See RETRIEVING DIAGNOSTIC TROUBLE CODES under SELF-DIAGNOSTIC SYSTEM. If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.