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Engine Controls - Basic Testing: Diagnosis Mazda MX-5 NA

Testing & Diagnostics 1 illustration ~274 words

VISUAL INSPECTION

Visually inspect all electrical wiring, looking for chafed, stretched, cut or pinched wiring. Ensure electrical connectors fit tightly and are not corroded. Ensure vacuum hoses are properly routed and are not pinched or cut. See VACUUM DIAGRAMS article to verify routing and connections (if necessary). Inspect air induction system for possible vacuum leaks.

INITIAL TEST

Check for any stored trouble codes and repair as necessary. See appropriate TESTS W/CODES article. Using a high-output spark plug tester, check for spark at all spark plugs. If spark is present at ALL spark plugs, go to CHECK PROFILE IGNITION PICKUP (PIP) AT ICM. If no spark is indicated or spark only occurs at some spark plugs, go to CHECKING PLUGS & WIRES.

Scheme 1

Scheme 1: CHECK PROFILE IGNITION PICKUP (PIP) AT ICM
  1. Turn key off. Connect ICM Diagnostic Cable (007-00059) to Breakout Box (T83L-50-EEC-IV), ICM and coil pack. DO NOT connect crankshaft Variable Reluctance Sensor (VRS) tee. (Scheme 1) Use ICM No. 6 overlay.
  2. Connect ICM diagnostic cable negative lead to battery, leaving positive lead disconnected. Set ICM diagnostic cable box to 4/6 CYLINDER position. Connect LED test light leads between breakout box pins No. J43 (PIP E) and J7 (ground). Crank engine. If LED test light blinks, go to step 3). If test light does not blink, go to ISOLATE ICM/PIP FAULT.
  3. Turn key off. Disconnect PCM. Check continuity of PIP and Ignition Ground (IGND) wires between ICM and PCM. see scheme 9 If any problems are found, repair circuits and components. Clear Continuous Memory, and run QUICK TEST in TESTS W/CODES article. If continuity is present and wires are not shorted or open, replace ICM.