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Contents Wiring diagrams Section: Engine Control System & Component Testing - 4-CYLINDER All sections

Highlander, MR2 & RAV4 Toyota Echo I

Engine Control System & Component Testing - 4-CYLINDER 2 illustrations ~1302 words

Highlander, MR2 & RAV4

Testing information is not available from manufacturer.

Scheme 121

Scheme 121: Corolla
Scheme 121: Corolla
  1. If Toyota hand-held tester is available, go to next step. If Toyota hand-held tester is not available, go to step 10.
  2. Connect hand-held tester to data link connector No. 3 at driver's side of instrument panel. (Scheme 126) Turn ignition on and then turn hand-held tester on. Start engine and turn A/C switch to ON position. Ensure A/C clutch engages.
  3. Select ACTIVE TEST MODE on hand-held tester. Check operation of A/C clutch when A/C-cut control is operated by hand-held tester. A/C clutch should turn off (stop operating) when A/C-cut control is operated by hand-held tester. If A/C clutch does not operate properly, go to next step. If A/C clutch operates properly, shut engine off. Remove hand-held tester. Diagnose by symptom. See «TROUBLE SHOOTING - NO CODES»(ref-133220) article.
  4. Check for open and short in wiring harness and electrical connectors between Engine Control Module (ECM) and A/C amplifier. See WIRING DIAGRAMS in appropriate article in AIR CONDITIONING & HEATING. ECM is located behind stereo on instrument panel, just in front of center console. For illustration of ECM location, see «THEORY & OPERATION»(ref-133195) article. A/C amplifier is located behind instrument panel, just above glove box, near center of glove box area. (Scheme 121) If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector is defective, repair as necessary.
  5. Remove necessary components for access to ECM. See «ENGINE CONTROL MODULE»(ref-133226-S19804702592002021900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
  6. Remove bolts from ECM so electrical connectors can be accessed. Note ECM electrical connector terminals. (Scheme 136)and (Scheme 137).
  7. Start engine. On 3-speed A/T and M/T models, using voltmeter, check voltage between body ground and terminal No. 21 (Red/Blue wire) at ECM electrical connector E6 while turning A/C switch from ON to OFF positions. (Scheme 136) This is the ACT terminal at ECM. On 4-speed A/T models, using voltmeter, check voltage between body ground and terminal No. 12 (Red/Blue wire) at ECM electrical connector E10 while turning A/C switch from ON to OFF positions. (Scheme 137) This is the ACT terminal at ECM.
  8. On all models, voltage should be 9-14 volts with A/C switch in ON position and less than 1.5 volts with A/C switch in OFF position. If voltage is as specified, go to next step. If voltage is not as specified, check for open and short in wiring harness and electrical connectors between ECM and A/C amplifier. See WIRING DIAGRAMS in appropriate article in AIR CONDITIONING & HEATING. A/C amplifier is located behind instrument panel, just above glove box, near center of glove box area. (Scheme 121) If wiring harness and electrical connectors are okay, replace A/C amplifier. If wiring harness or electrical connector is defective, repair as necessary.
  9. Check ECM ground circuit. See «WIRING DIAGRAMS»(ref-133228) article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM.
  10. Remove necessary components for access to Engine Control Module (ECM). See «ENGINE CONTROL MODULE»(ref-133226-S19804702592002021900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
  11. Remove bolts from ECM so electrical connectors can be accessed on ECM. Note ECM electrical connector terminals. (Scheme 136)and (Scheme 137).
  12. Start engine. On 3-speed A/T and M/T models, using voltmeter, check voltage between body ground and terminal No. 21 (Red/Blue wire) at ECM electrical connector E6 while turning A/C switch from ON to OFF positions. This is the ACT terminal at ECM. On 4-speed A/T models, using voltmeter, check voltage between body ground and terminal No. 12 (Red/Blue wire) at ECM electrical connector E10 while turning A/C switch from ON to OFF positions. This is the ACT terminal at ECM.
  13. On all models, voltage should be 9-14 volts with A/C switch in ON position and less than 1.5 volts with A/C switch in OFF position. If voltage is not as specified, go to next step. If voltage is as specified, check ECM ground circuit. See «WIRING DIAGRAMS»(ref-133228) article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM.
  14. Check for open and short in wiring harness and electrical connectors between ECM and A/C amplifier. See WIRING DIAGRAMS in appropriate article in AIR CONDITIONING & HEATING. A/C amplifier is located behind instrument panel, just above glove box, near center of glove box area. (Scheme 121) If wiring harness and electrical connectors are okay, replace A/C amplifier. If wiring harness or electrical connector is defective, repair as necessary.
WARNINGRead service precautions before proceeding with service procedure. See SERVICE PRECAUTIONS .

Scheme 122

Scheme 122
Scheme 122
  1. If Toyota hand-held tester is available, go to next step. If Toyota hand-held tester is not available, go to step 7.
  2. Connect hand-held tester to data link connector No. 3 at driver's side of instrument panel. (Scheme 130) Turn ignition on and then turn hand-held tester on. Start engine and turn A/C switch to ON position. Ensure A/C clutch engages.
  3. Select ACTIVE TEST MODE on hand-held tester. Check operation of A/C clutch when A/C-cut control is operated by hand-held tester. A/C clutch should turn off (stop operating) when A/C-cut control is operated by hand-held tester. If A/C clutch does not operate properly, go to next step. If A/C clutch operates properly, shut engine off. Remove hand-held tester. Diagnose by symptom. See «TROUBLE SHOOTING - NO CODES»(ref-133220) article.
  4. Check for open and short in wiring harness and electrical connectors between Engine Control Module (ECM) and A/C amplifier. See WIRING DIAGRAMS in appropriate article in AIR CONDITIONING & HEATING. ECM is located behind glove box. (Scheme 122) A/C amplifier is attached to rear of center cluster module control. (Scheme 122) If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector is defective, repair as necessary.
  5. Remove ECM with electrical connectors still attached. See «ENGINE CONTROL MODULE»(ref-133226-S19804702592002021900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
  6. Note ECM electrical connector terminals. (Scheme 141) Start engine. Using voltmeter, check voltage between body ground and terminal No. 22 (Pink/Green wire) at ECM electrical connector E10 while turning A/C switch from ON to OFF positions. This is the ACT terminal at ECM. Voltage should be 9-14 volts with A/C switch in ON position and less than 1.5 volts with A/C switch in OFF position. If voltage is not as specified, replace A/C amplifier. If voltage is as specified, check ECM ground circuit. See «WIRING DIAGRAMS»(ref-133228) article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM.
  7. Remove ECM with electrical connectors still attached. ECM is located behind glove box. (Scheme 122) See «ENGINE CONTROL MODULE»(ref-133226-S19804702592002021900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
  8. Note ECM electrical connector terminals. (Scheme 141) Start engine. Using voltmeter, check voltage between body ground and terminal No. 22 (Pink/Green wire) at ECM electrical connector E10 while turning A/C switch from ON to OFF positions. This is the ACT terminal at ECM. Voltage should be 9-14 volts with A/C switch in ON position and less than 1.5 volts with A/C switch in OFF position. If voltage is not as specified, go to next step. If voltage is as specified, check ECM ground circuit. See «WIRING DIAGRAMS»(ref-133228) article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM.
  9. Check for open and short in wiring harness and electrical connectors between ECM and A/C amplifier. See WIRING DIAGRAMS in appropriate article in AIR CONDITIONING & HEATING. A/C amplifier is attached to rear of center cluster module control. (Scheme 122) If wiring harness and electrical connectors are okay, replace A/C amplifier. If wiring harness or electrical connector is defective, repair as necessary.

Testing information is not available from manufacturer.