Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Leak Detection Pump
Disconnect negative battery cable. Remove EVAP system leak detection pump.
- Air Flow Inspection
Blow air into port "A" (charcoal canister side). Air should flow from port "B". See Fig 1 . If air does not flow from port "B" (air filter side), replace EVAP system leak detection pump. Blow air into port "B". Air should flow from port "A". If air does not flow from port "A", replace EVAP system leak detection pump. If EVAP system leak detection pump is as specified, go to next step. - Resistance Inspection
Disconnect negative battery cable. Disconnect EVAP system leak detection pump connector. Using DVOM, check resistance between appropriate terminals on EVAP system leak detection pump. See Fig 2 . See EVAP SYSTEM LEAK DETECTION PUMP RESISTANCE SPECIFICATIONΒ table. If resistance readings are not as specified, replace EVAP system leak detection pump. If resistance readings are within specification, check for open or short circuit in wiring harness. Disconnect PCM and install 104-Pin Breakout Box (49-UN01-130) between PCM and PCM harness connector. See Figure . Go to next step.Courtesy of MAZDA MOTORS CORP.
EVAP SYSTEM LEAK DETECTION PUMP RESISTANCE SPECIFICATIONTerminals Resistance (ohms) A-B 20-25 A-C 26.6-32.4 A-D About 118 - Open Circuit Inspection
Check continuity between following terminals.- EVAP system leak detection pump terminal "A" (White/Red wire) and main relay terminal "D" (Yellow wire).
- EVAP system leak detection pump terminal "B" (Black wire) and ground.
- EVAP system leak detection pump terminal "C" (Red/Blue wire) and breakout box terminal No. 67.
- EVAP system leak detection pump terminal "D" (Pink/Blue wire) and breakout box terminal No. 43.
See Fig 3 . See WIRING DIAGRAMS article. If continuity is not present, repair or replace open wiring harness.
- Short Circuit Inspection
Check for continuity between following:- EVAP system leak detection pump terminals "B" (Black wire), "C" (Red/Blue wire) and "D" (Pink/Blue wire) and power.
- EVAP system leak detection pump terminal "A" (White/Red wire) and ground.
If continuity is present, repair or replace shorted wiring harness.
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- β’ You smell fuel, burning insulation, or see smoke.
- β’ Brakes feel soft, pull hard to one side, or make grinding noises.
- β’ The engine overheats, stalls repeatedly, or misfires under load.
- β’ You are missing required tools, torque specs, or safe lifting equipment.
- β’ You are not confident in the next step or safety outcome.