Engine Controls - System/component Tests - Efi: Diagnosis Mazda MX-5 NA

Oil Passage Inspection

Ensure engine is cool. Remove oil return pipe. Verify oil passage in turbocharger and oil return pipe are not blocked with carbonized oil. Replace turbocharger and return pipe as necessary.

Pinpoint Test B (IDM Failure Code 212)

1. With ignition off, connect ICM diagnostic cable to Breakout Box (BOB) and ICM module. DO NOT connect VR sensor tee or coil tee. Use ICM "6" overlay. Connect negative and positive leads of ICM diagnostic cable to battery. Set ICM diagnostic cable box switch to 4/6 CYLINDER position. Set DVOM on 20-volt AC scale. Start engine. Measure voltage between IDM DETECTOR (30) and BAT- (7) of diagnostic cable Ignition Diagnostic Monitor (IDM) at BOB. If pulses are present, IDM detector output will be 5-7 volts AC. If AC voltage is 5-7 volts, go to next step. If AC voltage is not 5-7 volts, go to step 3).
2. With ignition off, ICM module and PCM disconnected, disconnect ICM module from ICM module tee, leaving ICM diagnostic cable connected to vehicle harness connector. Set DVOM on 200-ohm scale. Connect PCM Breakout Box (BOB) to PCM harness connector. Measure resistance between IDM E (41) at BOB and terminal No. 4 at PCM BOB. If resistance is less than 5 ohms, IDM signal at PCM is okay. PCM does not respond to IDM signal. Replace PCM. Remove test equipment, and reconnect all components. Clear continuous memory codes, and rerun QUICK TEST. See QUICK TEST in «TESTS W/CODES»(ref-18270) article in the ENGINE PERFORMANCE section. If resistance is 5 ohms or more, IDM is open. Check connections and/or repair open circuit or replace harness. Remove test equipment, and reconnect all components. Clear continuous memory codes, and rerun QUICK TEST. See QUICK TEST in appropriate «TESTS W/CODES»(ref-18270) article in the ENGINE PERFORMANCE section.
3. With ignition off and IDM circuit disconnected, set DVOM on 20-volt AC scale. Push ICM IDM button at ICM diagnostic cable connector to BOB. Start engine, and measure voltage between diagnostic cable IDM DETECTOR (30) and BAT- (7) at BOB. If AC voltage is 5-7 volts, go to next step. If AC voltage is not 5-7 volts, IDM output from ICM module does not exist. Replace ICM module. Remove test equipment, and reconnect all components. Clear continuous memory codes, and rerun QUICK TEST. See QUICK TEST in «TESTS W/CODES»(ref-18270) article.
4. With ignition off and PCM disconnected, set DVOM on 20-volt AC scale. Crank engine, and measure voltage between diagnostic cable IDM DETECTOR (30) and BAT- (7) at BOB. If voltage is less than 5 volts, go to next step. If voltage is 5 volts or more, PCM is loading IDM signal. Replace PCM. Remove test equipment, and reconnect all components. Clear continuous memory codes, and rerun QUICK TEST. See QUICK TEST in «TESTS W/CODES»(ref-18270) article.
5. With ignition off and ICM module and PCM disconnected, disconnect ICM module from diagnostic cable module tee, leaving ICM diagnostic cable connected to vehicle harness connector. Set DVOM on 20-k/ohm scale. Measure resistance between IDM E (41) and BAT- (7) at BOB. If resistance is 10-k/ohms or more, go to next step. If resistance is less than 10-k/ohms, IDM is shorted low. Check connections and/or repair short circuit or replace harness. Remove test equipment, and reconnect all components. Clear continuous memory codes, and rerun QUICK TEST. See QUICK TEST in «TESTS W/CODES»(ref-18270) article in the ENGINE PERFORMANCE section.
6. With ignition off and ICM module and PCM disconnected, set DVOM on 20-volt DC scale. With Key On Engine Off (KOEO), measure voltage between IDM E (41) and BAT- (7) at BOB. If DC voltage is .5 volt or more, IDM is shorted high. Check connections and/or repair short circuit or replace harness. Remove test equipment, and reconnect all components. Clear continuous memory codes, and rerun QUICK TEST. See QUICK TEST in «TESTS W/CODES»(ref-18270) article.
7. If voltage is less than .5 volt, IDM is shorted to another wire between ICM module and PCM. Check connections and/or repair short circuit or replace harness. Remove test equipment and reconnect all components. Clear continuous memory codes, and rerun QUICK TEST. See QUICK TEST in «TESTS W/CODES»(ref-18270) article in the ENGINE PERFORMANCE section.

Pinpoint Test C (Lack Of Power Or Poor Fuel Economy Code 213)

1. With ignition off, install ICM diagnostic cable to BOB and ICM module. DO NOT connect VR sensor tee or coil tee. Use ICM 6 overlay. Connect negative and positive leads of ICM diagnostic cable to battery. Set ICM diagnostic cable box switch to 4/6 CYLINDER position. Connect timing light (must be ICM compatible). Start engine, and warm it to normal operating temperature. Push and hold down ICM diagnostic cable SAW detector button. If timing is 8-12 degrees BTDC, go to next step. If timing is not 8-12 degrees BTDC, go to step 8).
2. Release ICM diagnostic cable SAW detector button. Go to next step if timing is not 15 degrees BTDC. If timing is more than 15 degrees BTDC, ICM is okay. Check for other causes of driveability symptoms.
3. With ignition off, set DVOM on 20-volt AC scale. Start engine and measure voltage between SAW DETECTOR (21) of ICM diagnostic cable and BAT- (7) at BOB. If AC voltage is 5 volts or more, go to next step. If AC voltage is less than 5 volts, SAW input to ICM module is okay and no spark advance is present. Replace ICM module. Remove test equipment, and reconnect all components. Clear continuous memory codes, and rerun QUICK TEST. See QUICK TEST in «TESTS W/CODES»(ref-18270) article.
4. With ignition off and SAW circuit disconnected, set DVOM on 20-volt AC scale. Push and hold down SAW detector button at ICM diagnostic cable connector to BOB. Start engine, and measure voltage between SAW DETECTOR (21) of ICM diagnostic cable and BAT- (7) at BOB. If AC voltage is less than 5 volts, go to next step. If AC voltage is 5 volts or more, SAW is shorted in ICM module. Replace ICM module. Remove test equipment, and reconnect all components. Clear continuous memory codes, and rerun QUICK TEST. See QUICK TEST in «TESTS W/CODES»(ref-18270) article in the ENGINE PERFORMANCE section.
5. With ignition off and ICM module and PCM disconnected, disconnect ICM module from ICM module tee, leaving ICM diagnostic cable connected to vehicle harness connector. Set DVOM on 20-k/ohm scale. Disconnect ICM diagnostic cable positive lead to battery. Measure resistance between SAW E (45) and BAT- (7) at BOB. If resistance is 10 k/ohms or more, go to next step. If resistance is less than 10 k/ohms, SAW is shorted low. Check connections and/or repair open circuit or replace harness. Remove test equipment, and reconnect all components. Clear continuous memory codes, and rerun QUICK TEST. See QUICK TEST in «TESTS W/CODES»(ref-18270) article.
6. With ignition off and ICM module and PCM disconnected, set DVOM on 20-volt DC scale. With Key On Engine Off (KOEO), measure voltage between SAW E (45) and BAT- (7) at BOB. If DC voltage is less than .5 volt, go to next step. If DC voltage is .5 volt or more, SAW is shorted high. Check connections and/or repair open circuit or replace harness. Remove test equipment, and reconnect all components. Clear continuous memory codes, and rerun QUICK TEST. See QUICK TEST in «TESTS W/CODES»(ref-18270) article in the ENGINE PERFORMANCE section.
7. With ignition off and ICM module and PCM disconnected, set DVOM on 200-ohm scale. Connect PCM Breakout Box (BOB) to PCM harness connector. Measure resistance between SAW E (45) at BOB and terminal No. 36 at PCM BOB. If resistance is less than 5 ohms, SAW is open. Check connections and/or repair open circuit or replace harness. Remove test equipment, and reconnect all components. Clear continuous memory codes, and rerun QUICK TEST. See QUICK TEST in appropriate «TESTS W/CODES»(ref-18270) article. If resistance is 5 ohms or more, SAW is not being transmitted by ECU. Replace ECU. Remove test equipment, and reconnect all components. Clear continuous memory codes, and rerun QUICK TEST. See QUICK TEST in «TESTS W/CODES»(ref-18270) article.
8. If VR sensor or trigger wheel is loose, misaligned or damaged, repair or replace as necessary. Remove test equipment, and reconnect all components. Clear continuous memory codes, and rerun QUICK TEST. See QUICK TEST in «TESTS W/CODES»(ref-18270) article in the ENGINE PERFORMANCE section. If VR sensor or trigger wheel is not loose, misaligned or damaged, ICM module has incorrect output. Remove test equipment, and reconnect all components. Clear continuous memory codes, and rerun QUICK TEST. See QUICK TEST in «TESTS W/CODES»(ref-18270) article.

Pinpoint Test D (No Start Or Coil Failure Code 232)

1. Using spark plug tester, check for spark at all spark plug wires while cranking. If spark was consistent on all spark plug wires (one spark per crankshaft revolution), ignition system is okay. Check for other causes of driveability symptoms. If spark was not consistent on all spark plug wires, check spark plug wires for insulation damage, looseness, shorting and other damage. Remove and check spark plugs for wear, carbon deposits, improper gap and damage. If spark plugs and wires are okay, go to next step. If spark plugs and wires are not okay, repair or replace as necessary. Remove test equipment, and reconnect all components. Clear continuous memory codes, and rerun QUICK TEST. See QUICK TEST in «TESTS W/CODES»(ref-18270) article.
2. With ignition off, install ICM diagnostic cable to BOB. Connect ICM diagnostic cable negative lead to battery. Set ICM diagnostic cable box switch to 4/6 CYLINDER position. Install coil tee. Use ICM "6" overlay. Set DVOM on 20-volt DC scale. With Key On, Engine Off (KOEO), measure voltage between VBAT C (5) and BAT- (7) at BOB. If DC voltage is 10 volts or more, go to next step. If DC voltage is less than 10 volts, VBAT is open. Check connections and/or repair open circuit or replace harness. Remove test equipment, and reconnect all components. Clear continuous memory codes, and rerun QUICK TEST. See QUICK TEST in «TESTS W/CODES»(ref-18270) article.
3. With Key On Engine Off (KOEO), measure voltage between C1C (3) and BAT- (7) at BOB. If DC voltage is 10 volts or more, go to next step. If DC voltage is less than 10 volts, go to step 15).
4. With Key On Engine Off (KOEO), measure voltage between C2C (6) and BAT- (7) at BOB. If DC voltage is 10 volts or more, go to next step. If DC voltage is less than 10 volts, go to step 17).
5. With Key On Engine Off (KOEO), measure voltage between C3C (6) and BAT- (7) at BOB. If DC voltage is 10 volts or more, go to next step. If DC voltage is less than 10 volts, go to step 19).
6. With ignition off, connect ICM module tee to ICM module and vehicle harness connector. Set DVOM on 20-volt DC scale. With KOEO, measure voltage between C1E (53) and BAT- (7) at BOB. If DC voltage is 10 volts or more, go to next step. If DC voltage is less than 10 volts, C1 is open. Check connections and/or repair open circuit or replace harness. Remove test equipment, and reconnect all components. Clear continuous memory codes, and rerun QUICK TEST. See QUICK TEST in «TESTS W/CODES»(ref-18270) article in the ENGINE PERFORMANCE section.
7. With KOEO, measure voltage between C2E (55) and BAT- (7) at BOB. If DC voltage is 10 volts or more, go to next step. If DC voltage is less than 10 volts, C2 is open. Check connections and/or repair open circuit or replace harness. Remove test equipment, and reconnect all components. Clear continuous memory codes, and rerun QUICK TEST. See QUICK TEST in «TESTS W/CODES»(ref-18270) article.
8. With KOEO, measure voltage between C3E (54) and BAT- (7) at BOB. If DC voltage is 10 volts or more, go to next step. If DC voltage is less than 10 volts, C3 is open. Check connections and/or repair open circuit or replace harness. Remove test equipment, and reconnect all components. Clear continuous memory codes, and rerun QUICK TEST. See QUICK TEST in «TESTS W/CODES»(ref-18270) article in the ENGINE PERFORMANCE section.
9. With ignition off and coil disconnected, disconnect coil pack from coil tee. Leave ICM diagnostic cable connected to vehicle harness connector. Set DVOM on 20-volt DC scale. With KOEO, measure voltage between C1C (3) and BAT- (7) at BOB. If voltage is less than .5 volt, go to next step. If voltage is .5 volt or more, go to step 21).
10. With KOEO and coil disconnected, measure voltage at BOB between C2C (6) and BAT- (7). If DC voltage is less than .5 volt, go to next step. If DC voltage is .5 volt or more, go to step 22).
11. With KOEO and coil disconnected, measure voltage at BOB between C3C (10) and BAT- (7). If DC voltage is less than 10.5 volts, go to next step. If DC voltage is 10.5 volts or more, go to step 23).
12. With coil disconnected, connect ICM diagnostic cable positive lead to battery. Connect incandescent test light between C1C (3) and BAT+ (1). Crank engine. If test light blinks consistently and brightly (one blink per engine revolution), go to next step. If test light does not blink consistently and brightly, C1 is open in ICM module. Replace ICM module. Remove test equipment, and reconnect all components. Clear continuous memory codes, and rerun QUICK TEST. See QUICK TEST in «TESTS W/CODES»(ref-18270) article.
13. With coil disconnected, connect incandescent test light between C2C (6) and BAT+ (1). Crank engine. If test light blinks consistently and brightly (one blink per engine revolution), go to next step. If test light does not blink consistently and brightly, C2 is open in ICM module. Replace ICM module. Remove test equipment, and reconnect all components. Clear continuous memory codes, and rerun QUICK TEST. See QUICK TEST in «TESTS W/CODES»(ref-18270) article in the ENGINE PERFORMANCE section.
14. With coil disconnected, connect incandescent test light between C3C (10) and BAT+ (1). Crank engine. If test light blinks consistently and brightly (one blink per engine revolution), input to coil pack is okay and no high voltage output is present. Replace coil pack. Remove test equipment, and reconnect all components. Clear continuous memory codes, and rerun QUICK TEST. See QUICK TEST in «TESTS W/CODES»(ref-18270) article. If test light does not blink consistently and brightly, C3 is open in ICM module. Replace ICM module. Remove test equipment, and reconnect all components. Clear continuous memory codes, and rerun QUICK TEST. See QUICK TEST in «TESTS W/CODES»(ref-18270) article.
15. With ignition off and coil disconnected, set DVOM on 20-k/ohm scale. Disconnect coil from coil tee, leave ICM diagnostic cable connected to vehicle harness connector. Measure voltage at BOB between C1C (3) and BAT- (7). If resistance is less than 2 k/ohms, go to next step. If resistance is 2 k/ohms or more, C1 is open in coil. Replace coil pack. Remove test equipment, and reconnect all components. Clear continuous memory codes, and rerun QUICK TEST. See QUICK TEST in «TESTS W/CODES»(ref-18270) article in the ENGINE PERFORMANCE section.
16. With ignition off and ICM module and coil disconnected, disconnect ICM module from vehicle harness connector. Set DVOM on 20-k/ohm scale. Measure voltage between C1C (3) and BAT- (7) at BOB. If resistance is less than 10-k/ohms, C1 is shorted low. Check connections and/or repair open circuit or replace harness. Remove test equipment, and reconnect all components. Clear continuous memory codes, and rerun QUICK TEST. See QUICK TEST in «TESTS W/CODES»(ref-18270) article. If resistance is 10-k/ohms or more, C1 is shorted low. Replace ICM module. Remove test equipment, and reconnect all components. Clear continuous memory codes, and rerun QUICK TEST. See QUICK TEST in «TESTS W/CODES»(ref-18270) article in the ENGINE PERFORMANCE section.
17. With ignition off and coil disconnected, set DVOM on 20-k/ohm scale. Disconnect coil from coil tee, leave ICM diagnostic cable connected to vehicle harness connector. Measure resistance between C2C (6) and BAT- (7) at BOB. If resistance is less than 2k/ohms, go to next step. If resistance is 2 k/ohms or more, C2 is open in coil. Replace coil pack. Remove test equipment, and reconnect all components. Clear continuous memory codes, and rerun QUICK TEST. See QUICK TEST in «TESTS W/CODES»(ref-18270) article.
18. With ignition off and ICM module and coil disconnected, disconnect ICM module from vehicle harness connector. Set DVOM on 20-k/ohm scale. Measure resistance between C2C (6) and BAT- (7) at BOB. If resistance is less than 10 k/ohms, C2 is shorted low. Check connections and/or repair open circuit or replace harness. Remove test equipment, and reconnect all components. Clear continuous memory codes, and rerun QUICK TEST. See QUICK TEST in SELF-DIAGNOSTICS - NAVAJO article. If resistance is 10 k/ohms or more, C2 is shorted low. Replace ICM module. Remove test equipment, and reconnect all components. Clear continuous memory codes, and rerun QUICK TEST. See QUICK TEST in «TESTS W/CODES»(ref-18270) article in the ENGINE PERFORMANCE section.
19. With ignition off and coil disconnected, set DVOM on 20-k/ohm scale. Disconnect coil from coil tee, leave ICM diagnostic cable connected to vehicle harness connector. Measure resistance between C3C (10) and BAT- (7) at BOB. If resistance is less than2 k/ohms, go to next step. If resistance is 2 k/ohms or more, C3 is open in coil. Replace coil pack. Remove test equipment, and reconnect all components. Clear continuous memory codes, and rerun QUICK TEST. See QUICK TEST in «TESTS W/CODES»(ref-18270) article.
20. With ignition off and ICM module and coil disconnected, disconnect ICM module from vehicle harness connector. Set DVOM on 20-k/ohm scale. Measure resistance between C3C (10) and BAT- (7) at BOB. If resistance is less than 10 k/ohms, C3 is shorted low. Check connections and/or repair open circuit or replace harness. Remove test equipment, and reconnect all components. Clear continuous memory codes, and rerun QUICK TEST. See QUICK TEST in «TESTS W/CODES»(ref-18270) article. If resistance is 10 k/ohms or more, C3 is shorted low. Replace ICM module. Remove test equipment, and reconnect all components. Clear continuous memory codes, and rerun QUICK TEST. See QUICK TEST in «TESTS W/CODES»(ref-18270) article.
21. With ignition off and ICM module and coil disconnected, disconnect ICM module from ICM module tee. Leave ICM diagnostic cable connected to vehicle harness connector. Set DVOM on 20-volt DC scale. With KOEO, measure voltage between C1C (3) and BAT- (7) at BOB. If DC voltage is .5 volt or more, C1 is shorted high. Check connections and/or repair open circuit or replace harness. Remove test equipment, and reconnect all components. Clear continuous memory codes, and rerun QUICK TEST. See QUICK TEST in «TESTS W/CODES»(ref-18270) article. If DC voltage is less than .5 volt, C1 is shorted high. Replace ICM module. Remove test equipment, and reconnect all components. Clear continuous memory codes, and rerun QUICK TEST. See QUICK TEST in «TESTS W/CODES»(ref-18270) article.
22. With ignition off and ICM module and coil disconnected, disconnect ICM module from ICM module tee. Leave ICM diagnostic cable connected to vehicle harness connector. Set DVOM on 20-volt DC scale. With KOEO, measure voltage between C2C (6) and BAT- (7) at BOB. If DC voltage is .5 volt or more, C2 is shorted high. Check connections and/or repair open circuit or replace harness. Remove test equipment, and reconnect all components. Clear continuous memory codes, and rerun QUICK TEST. See QUICK TEST in «TESTS W/CODES»(ref-18270) article. If DC voltage is less than .5 volt, C2 is shorted high. Replace ICM module. Remove test equipment, and reconnect all components. Clear continuous memory codes, and rerun QUICK TEST. See QUICK TEST in «TESTS W/CODES»(ref-18270) article in the ENGINE PERFORMANCE section.
23. With ignition off and ICM module and coil disconnected, disconnect ICM module from ICM module tee. Leave ICM diagnostic cable connected to vehicle harness connector. Set DVOM on 20-volt DC scale. With KOEO, measure voltage between C3C (10) and BAT- (7) at BOB. If DC voltage is .5 volt or more, C3 is shorted high. Check connections and/or repair open circuit or replace harness. Remove test equipment, and reconnect all components. Clear continuous memory codes, and rerun QUICK TEST. See QUICK TEST in «TESTS W/CODES»(ref-18270) article. If DC voltage is less than .5 volt, C3 is shorted high. Replace ICM module. Remove test equipment, and reconnect all components. Clear continuous memory codes, and rerun QUICK TEST. See QUICK TEST in «TESTS W/CODES»(ref-18270) article in the ENGINE PERFORMANCE section.

System Inspection

1. Warm engine to normal operating temperature. Disconnect electrical connector from switching valve solenoid. Using jumper wires, energize solenoid.
2. If engine idles rough, air control valve and switching valve solenoid are okay. see scheme 58 If engine does not idle rough, check vacuum routing, switching valve solenoid, air pump and air control valve.

Purge system operation takes place when vehicle is accelerating in gear (off idle), engine is at operating temperature and oxygen sensor is functioning normally. (Scheme 23)

Scheme 23

1. Warm engine to normal operating temperature, and operate it at idle. Disconnect Positive Crankcase Ventilation (PCV) valve, together with vent hose, from valve cover. Block PCV valve opening and check for vacuum. If no vacuum is felt, check for collapsed line and blockage.
2. Note direction of valve installation. Remove PCV valve. Blow air into upper port of valve. Air should flow through valve from lower port. Blow air through lower port of valve. Air should not flow from upper port. Replace valve as necessary.