Engine Control System Self-Diagnostics Toyota Land Cruiser 100

DIAGNOSTIC TROUBLE CODE DEFINITIONS

DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION

DIAGNOSTIC TESTS

Note. Before performing any diagnostic test, refer to SELF-DIAGNOSTICS - INTRODUCTION article for diagnostic system functions and system diagnostic procedures. For component location, see appropriate illustration in THEORY & OPERATION article. To identify circuits and wire colors referenced in testing, see WIRING DIAGRAMS article. References to California emissions apply to vehicles with California emissions, which may be verified by underhood Emission Control label. Vehicles with California emissions may be available in other states.

Note. To identify ECM terminals referenced in testing, use illustration. (Scheme 1)

Scheme 1

DTC P0100: MASS AIRFLOW (MAF) METER CIRCUIT

Circuit Description

MAF meter uses a platinum hot wire maintained at a constant temperature. Airflow past sensor affects temperature and current flow through MAF meter. DTC is set when ECM detects an open or short in MAF meter circuit for more than 3 seconds with engine speed at 4000 RPM or less. ECM will operate in fail-safe mode if DTC P0100 is set. Possible causes are

1. MAF meter circuit is open or shorted.
2. Defective MAF meter.
3. Defective ECM.

Diagnostic Aids

After confirming DTC P0100, use scan tool to access CURRENT DATA to confirm mass airflow ratio. If ratio is 0.0 gm/sec., VG circuit may be open or shorted or power source circuit may be open. If ratio is 271.0 gm/sec. or more, EVG circuit may be open. Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

Diagnosis & Repair

1. Connect scan tool to Data Link Connector (DLC) No. 3. (Scheme 2) Start and warm engine to normal operating temperature. Using scan tool, monitor MAF flow rate. If scan tool reading is 0.0 gm/sec., go to next step. If scan tool reading is 271 gm/sec. or more, go to step 5.
2. Turn ignition off. Disconnect MAF meter harness connector. Turn ignition on. Measure voltage between ground and terminal No. 3 (Black/Yellow wire) at MAF meter harness connector. (Scheme 3) If voltage is 9-14 volts, go to next step. If voltage is not 9-14 volts, repair open in Black/Yellow wire between EFI main relay and MAF meter. See WIRING DIAGRAMS article.
3. Turn ignition off. Connect MAF meter harness connector. Access ECM behind glove box. Ensure shift lever is in Neutral or Park. Ensure A/C switch is off. Start engine and let idle. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 10 (Blue/Yellow wire) at ECM harness connector E6. (Scheme 1) If voltage is not.5-3.0 volts, go to next step. If voltage is.5-3.0 volts, replace ECM.
4. Check for open or short in Blue/Yellow wire between MAF meter and ECM. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, replace MAF meter.
5. Turn ignition off. Access ECM behind glove box. Using DVOM, backprobe ECM harness connector and measure resistance between ground and terminal No. 19 (Green/White wire) at ECM harness connector E6. (Scheme 1) If resistance is one ohms or less, go to next step. If resistance is greater than one ohm, replace ECM.
6. Check for open in Green/White wire between MAF meter and ECM. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, replace MAF meter.

Scheme 2

Scheme 3

MAF meter uses a platinum hot wire maintained at a constant temperature. Airflow past sensor affects temperature and current flow through MAF meter. DTC is set when ECM detects either throttle valve is fully closed and MAF meter output is more than 2.2 volts for more than 10 seconds with engine speed of 900 RPM or less, or VTA circuit signal is .63 volt or more and MAF meter output is less than one volt for more than 10 seconds with engine speed of 1500 RPM or more. ECM will operate in fail-safe mode if DTC P0101 is set. Possible cause is

1. Defective MAF meter.

After confirming DTC P0101, use scan tool to access CURRENT DATA to confirm mass airflow ratio. If ratio is 0.0 gm/sec., VG circuit may be open or shorted or power source circuit may be open. If ratio is 271.0 gm/sec. or more, EVG circuit may be open. Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

If only DTC P0101 is displayed, replace MAF meter. If other DTCs are displayed, diagnose and repair those DTCs first and retest.

DTC P0110: INTAKE AIR TEMPERATURE (IAT) SENSOR CIRCUIT

Note. If DTCs P0110, P0115, P0120, P0450 and P1120 are output together, check circuit E2 (Brown/White wire) between terminal No. 18 at ECM harness connector E6 and splice E10. Repair as necessary. See WIRING DIAGRAMS article.

IAT sensor is a thermistor built into MAF meter and is used to monitor temperature of air flowing through MAF meter. DTC is set when ECM detects an open or short in IAT sensor circuit. ECM will operate in fail-safe mode if DTC P0110 is set. Possible causes are

1. IAT sensor circuit is open or shorted.
2. Defective IAT sensor (built into MAF meter).
3. Defective ECM.

After confirming DTC P0110, use scan tool to access CURRENT DATA to confirm air intake temperature. If temperature displayed on scan tool is -40°F (-40°C), IAT sensor circuit may be open. If temperature displayed on scan tool is 284°F (140°C) or more, IAT sensor circuit may be shorted. Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

1. Connect scan tool to Data Link Connector (DLC) No. 3. (Scheme 2) Turn ignition on. Using scan tool, monitor IAT sensor temperature. If temperature displayed on scan tool is same as outside temperature, problem is intermittent. Check component and ECM connections. If temperature displayed on scan tool is -40°F (-40°C), go to next step. If temperature displayed on scan tool is 284°F (140°C) or more, go to step 4.
2. Turn ignition off. Disconnect MAF meter harness connector. Using a jumper wire, connect MAF meter harness connector terminals No. 1 (Brown/White wire) and No. 2 (Yellow/Black wire). (Scheme 3) Turn ignition on. Using scan tool, monitor IAT sensor temperature. If temperature displayed on scan tool is 284°F (140°C) or more, replace MAF meter. If temperature displayed on scan tool is less than 284°F (140°C), go to next step.
3. Turn ignition off. Remove jumper wire. Access ECM behind glove box. Using a jumper wire, backprobe between terminals No. 18 (Brown/White wire) and No. 22 (Yellow/Black wire) at ECM harness connector E6. (Scheme 1) If temperature displayed on scan tool is 284°F (140°C) or more, repair open in Yellow/Black wire and/or Brown/White wire between MAF meter and ECM. See WIRING DIAGRAMS article. If temperature displayed on scan tool is less than 284°F (140°C), replace ECM.
4. Turn ignition off. Disconnect MAF meter harness connector. Turn ignition on. If temperature displayed on scan tool is -40°F (-40°C), replace MAF meter. If temperature displayed on scan tool is not -40°F (-40°C), go to next step.
5. Turn ignition off. Access ECM behind glove box. Disconnect ECM harness connector E6. (Scheme 1) Turn ignition on. If temperature displayed on scan tool is -40°F (-40°C), repair short in Yellow/Black wire between MAF meter and ECM. See WIRING DIAGRAMS article. If temperature displayed on scan tool is not -40°F (-40°C), replace ECM.

DTC P0115: ENGINE COOLANT TEMPERATURE (ECT) SENSOR CIRCUIT

Note. If DTCs P0110, P0115, P0120, P0450 and P1120 are output together, check circuit E2 (Brown/White wire) between terminal No. 18 at ECM harness connector E6 and splice E10. Repair as necessary. See WIRING DIAGRAMS article.

ECT sensor is a thermistor sensor which monitors water temperature. DTC is set when ECM detects an open or short in ECT sensor circuit. Possible causes are

1. ECT sensor circuit is open or shorted.
2. Defective ECT sensor.
3. Defective ECM.

After confirming DTC P0115, use scan tool to access CURRENT DATA to confirm engine coolant temperature. If temperature displayed on scan tool is -40°F (-40°C), ECT sensor circuit may be open. If temperature displayed on scan tool is 284°F (140°C) or more, ECT sensor circuit may be shorted. Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

1. Connect scan tool to Data Link Connector (DLC) No. 3. (Scheme 2) Turn ignition on. Using scan tool, monitor ECT sensor temperature. If temperature displayed on scan tool is same as actual coolant temperature, problem is intermittent. Check component and ECM connections. If temperature displayed on scan tool is -40°F (-40°C), go to next step. If temperature displayed on scan tool is 284°F (140°C) or more, go to step 4.
2. Turn ignition off. Disconnect ECT sensor harness connector (2-pin harness connector with Green/Black wire and Brown/White wire). Using a jumper wire, connect ECT sensor harness connector terminals. Turn ignition on. Using scan tool, monitor ECT sensor temperature. If temperature displayed on scan tool is less than 284°F (140°C), go to next step. If temperature displayed on scan tool is 284°F (140°C) or more, replace ECT sensor.
3. Turn ignition off. Remove jumper wire. Access ECM behind glove box. Using a jumper wire, backprobe between terminals No. 18 (Brown/White wire) and No. 14 (Green/Black wire) at ECM harness connector E6. (Scheme 1) If temperature displayed on scan tool is 284°F (140°C) or more, repair open in Green/Black wire and/or Brown/White wire between ECT sensor and ECM. See WIRING DIAGRAMS article. If temperature displayed on scan tool is less than 284°F (140°C), replace ECM.
4. Turn ignition off. Disconnect ECT sensor harness connector. Turn ignition on. If temperature displayed on scan tool is -40°F (-40°C), replace ECT sensor. If temperature displayed on scan tool is not -40°F (-40°C), go to next step.
5. Turn ignition off. Access ECM behind glove box. Disconnect ECM harness connector E6. (Scheme 1) Turn ignition on. If temperature displayed on scan tool is -40°F (-40°C), repair short in Green/Black wire between ECT sensor and ECM. See WIRING DIAGRAMS article. If temperature displayed on scan tool is not -40°F (-40°C), replace ECM.

DTC P0116: ENGINE COOLANT TEMPERATURE (ECT) SENSOR CIRCUIT RANGE/PERFORMANCE

Note. If DTC P0115 and DTC P0116 are output together, ECT sensor circuit may be open. Diagnosis and repair DTC P0115 first. See DTC P0115: ENGINE COOLANT TEMPERATURE (ECT) SENSOR CIRCUIT .

ECT sensor is a thermistor sensor which monitors water temperature. DTC is set when ECT sensor signal value is out of range during engine operation. Possible causes are

1. Defective ECT sensor.
2. Defective cooling system.

After confirming DTC P0116, use scan tool to access CURRENT DATA to confirm engine coolant temperature. If temperature displayed on scan tool is -40°F (-40°C), ECT sensor circuit may be open. If temperature displayed on scan tool is 284°F (140°C) or more, ECT sensor circuit may be shorted. Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

1. If any other DTCs are displayed, diagnose and repair those DTCs first and retest. If only DTC P0116 is displayed, go to next step.
2. Remove and inspect cooling system thermostat. If problem exists, replace thermostat as necessary and retest. If problem does not exist, replace ECT sensor.

DTC P0120: THROTTLE POSITION (TP) SENSOR CIRCUIT

Note. If DTCs P0110, P0115, P0120, P0450 and P1120 are output together, check circuit E2 (Brown/White wire) between terminal No. 18 at ECM harness connector E6 and splice E10. Repair as necessary. See WIRING DIAGRAMS article.

TP sensor is located on throttle body and has 2 variable resistors integral to TP sensor. TP sensor monitors throttle opening. ECM determines vehicle driving condition and adjusts air/fuel mixture accordingly. DTC is set when ECM detects voltage is out of range on VTA or VTA2 circuits. Possible causes are

1. TP sensor circuit is open or shorted.
2. Defective TP sensor.
3. Defective ECM.

After confirming DTC P0120, use scan tool to access CURRENT DATA to confirm throttle valve opening percentage with throttle open and closed. If percentage displayed on scan tool is always zero percent, VC circuit may be open, or VTA circuit may be open or shorted. If percentage displayed on scan tool is always 8-20 percent, VTA2 circuit may be open or shorted. If percentage displayed on scan tool is always 100 percent, E2 circuit may be open. Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

Diagnosis & Repair (Using Toyota Hand-Held Tester)

1. Connect scan tool to Data Link Connector (DLC) No. 3. (Scheme 2) Turn ignition on. Using Toyota hand-held tester, monitor throttle valve opening percentage for VTA circuit and read voltage for VTA2 circuit. Throttle opening percentage for VTA circuit should be 8-20 percent with fully closed throttle and should be 64-96 percent with fully open throttle (WOT). Voltage reading for VTA2 circuit should be 2.0-2.9 volts with fully closed throttle and 4.7-5.1 volts with fully open throttle. If values are as specified, replace ECM. If values are not as specified, go to next step.
2. Access ECM behind glove box. Turn ignition on. Using DVOM, backprobe ECM harness connector and measure voltage between terminals No. 2 (Blue/Red wire) and No. 18 (Brown/White wire) at ECM harness connector E6. (Scheme 1) If voltage is 4.5-5.5 volts, go to next step. If voltage is not 4.5-5.5 volts, replace ECM.
3. Using DVOM, backprobe ECM harness connector and measure voltage between terminals No. 18 (Brown/White wire) and No. 13 (Red/Yellow wire) at ECM harness connector E6. With fully closed throttle, voltage should be.4-1.0 volt. With valve fully open throttle, voltage should be 3.2-4.8 volts. Using DVOM, backprobe ECM harness connector and measure voltage between terminals No. 18 (Brown/White wire) and No. 20 (Yellow/Black wire) at ECM harness connector E6. With fully closed throttle, voltage should be 2.0-2.9 volts. With fully open throttle, voltage should be 4.7-5.1 volts. If voltage readings are as specified, replace ECM. If voltage readings are not as specified, go to next step.
4. Check Throttle Position (TP) sensor. See THROTTLE BODY under IDLE CONTROL SYSTEMS in SYSTEM & COMPONENT TESTING - V6 & V8 article. If problem exists, replace TP sensor. If problem does not exist, check for an open or short in wiring between ECM and TP sensor. See WIRING DIAGRAMS article. Repair wiring harness as necessary.

Diagnosis & Repair (Using OBD-II Scan Tool)

1. Access ECM behind glove box. Turn ignition on. Using DVOM, backprobe ECM harness connector and measure voltage between terminals No. 2 (Blue/Red wire) and No. 18 (Brown/White wire) at ECM harness connector E6. (Scheme 1) If voltage is 4.5-5.5 volts, go to next step. If voltage is not 4.5-5.5 volts, replace ECM.
2. Using DVOM, backprobe ECM harness connector and measure voltage between terminals No. 18 (Brown/White wire) and No. 13 (Red/Yellow wire) at ECM harness connector E6. With fully closed throttle, voltage should be.4-1.0 volt. With fully open throttle, voltage should be 3.2-4.8 volts. Using DVOM, backprobe ECM harness connector and measure voltage between terminals No. 18 (Brown/White wire) and No. 20 (Yellow/Black wire) at ECM harness connector E6. With fully closed throttle, voltage should be 2.0-2.9 volts. With fully open throttle, voltage should be 4.7-5.1 volts. If voltage readings are as specified, replace ECM. If voltage readings are not as specified, go to next step.
3. Check Throttle Position (TP) sensor. See THROTTLE BODY under IDLE CONTROL SYSTEMS in SYSTEM & COMPONENT TESTING - V6 & V8 article. If problem exists, replace TP sensor. If problem does not exist, check for an open or short in wiring between ECM and TP sensor. See WIRING DIAGRAMS article. Repair wiring harness as necessary.

TP sensor is located on throttle body and has 2 variable resistors integral to TP sensor. TP sensor monitors throttle opening. ECM determines vehicle driving condition and adjusts air/fuel mixture accordingly. DTC is set when ECM detects TP sensor output voltage is out of range during vehicle operation. Possible cause is

1. Defective Throttle Position (TP) sensor.

After confirming DTC P0121, use scan tool to access CURRENT DATA to confirm throttle valve opening percentage with throttle open and closed. If percentage displayed on scan tool is always zero percent, VC circuit may be open, or VTA circuit may be open or shorted. If percentage displayed on scan tool is always 8-20 percent, VTA2 circuit may be open or shorted. If percentage displayed on scan tool is always 100 percent, E2 circuit may be open. Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

If any other DTCs are displayed, diagnose and repair those DTCs first and retest. If only DTC P0121 is displayed, replace TP sensor.

DTC P0125: INSUFFICIENT COOLANT TEMPERATURE FOR CLOSED LOOP FUEL CONTROL

Note. Bank No. 1 refers to bank which includes cylinder No. 1. Bank No. 2 refers to bank without cylinder No. 1. Heated oxygen sensor No. 1 refers to sensor closest to engine block.

Heated oxygen sensor monitors exhaust gas oxygen content and delivers an input signal to ECM. ECM uses input signal to determine fuel injection system operation. Heated oxygen sensors include a heater. DTC is set when heated oxygen sensor No. 1 does not output a rich condition once engine is at normal operating temperature, engine speed of more than 1400 RPM and vehicle speed is 25-62 MPH for at least 2 minutes. Possible causes are

1. Heated oxygen sensor(s) No. 1 circuit is open or shorted.
2. Defective heated oxygen sensor(s) No. 1.
3. Air induction system malfunction.
4. Improper fuel pressure.
5. Defective fuel injector.
6. Vehicle has run out of fuel.
7. Exhaust system leak.
8. Defective ECM.

After confirming DTC P0125, use scan tool to access CURRENT DATA to confirm voltage output of heated oxygen sensors (banks No. 1 and 2, sensor No. 1). If voltage displayed on scan tool is always less than 0.1 volt, heated oxygen sensor circuit may be open or shorted. Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

1. If any other DTCs are displayed, diagnose and repair those DTCs first and retest. If only DTC P0125 is displayed, go to next step.
2. Connect scan tool to Data Link Connector (DLC) No. 3. (Scheme 2) Start and warm engine to normal operating temperature. Using scan tool, monitor each heated oxygen sensor No. 1 output voltage. Snap accelerate engine to about 4000 RPM 3 times. Both heated oxygen sensors No. 1 should indicate a rich signal (.45 volt or more) at least once. If a rich signal is indicated for both heated oxygen sensors No. 1 at least once, go to step 9. If either heated oxygen sensor No. 1 does not display a rich signal at least once, go to next step.
3. Check for open or short in wiring between appropriate heated oxygen sensor(s) No. 1 and ECM. If problem does not exist, go to next step. If problem exists, repair wiring as necessary. See WIRING DIAGRAMS article.
4. Using scan tool, check if a misfire has occurred by monitoring DTCs and DATA LIST. If a misfire has occurred, perform «DTC P0300: RANDOM MISFIRE DETECTED»(/toyota/land-cruiser/100-1998-2002/remont/testing-diagnostics/#engine-control-system-self-diagnostics). If misfire has not occurred, go to next step.
5. Ensure oil dipstick, oil filler cap, PCV system and all other air induction system components are intact and operating properly. If problem exists, repair as necessary. If problem does not exist, go to next step.
6. Check fuel pressure. See FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - V6 & V8 article. If fuel pressure is not within specification, repair as necessary. If fuel pressure is within specification, go to next step.
7. Check fuel injectors. See FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - V6 & V8 article. If problem exists, repair as necessary. If problem does not exist, go to next step.
8. Check exhaust system for leaks. If problem exists, repair as necessary. If problem does not exist, replace defective heated oxygen sensor(s) No. 1.
9. Perform test drive confirmation, then go to next step. See «TEST DRIVE CONFIRMATION»(/toyota/land-cruiser/100-1998-2002/remont/testing-diagnostics/#engine-control-system-self-diagnostics__test-drive-confirmation) under DTC P0130 OR P0150: HEATED OXYGEN SENSOR NO. 1 CIRCUIT.
10. Clear and recheck for DTCs. If DTC P0125 is displayed again, replace ECM. If DTC P0125 is not displayed again, go to next step.
11. Vehicle either ran out of fuel or problem is intermittent. Check component and ECM connections.

DTC P0130 OR P0150: HEATED OXYGEN SENSOR NO. 1 CIRCUIT

Note. Bank No. 1 refers to bank which includes cylinder No. 1. Bank No. 2 refers to bank without cylinder No. 1. Heated oxygen sensor No. 1 refers to sensor closest to engine block. DTC P0130 is for bank No. 1, sensor No. 1. DTC P0150 is for bank No. 2, sensor No. 1.

Heated oxygen sensor monitors exhaust gas oxygen content and delivers an input signal to ECM. ECM uses input signal to determine fuel injection system operation. Heated oxygen sensors include a heater. DTC P0130 is set when bank No. 1, sensor No. 1 voltage remains at .4 volt or more, or .55 volt or less during idle, once engine is at normal operating temperature. DTC P0150 is set when bank No. 2, sensor No. 1 voltage remains at .4 volt or more, or .55 volt or less during idle, once engine is at normal operating temperature. Possible causes are

1. Heated oxygen sensor(s) No. 1 circuit is open or shorted.
2. Defective heated oxygen sensor(s) No. 1.
3. Air induction system malfunction.
4. Improper fuel pressure.
5. Defective fuel injector.
6. Defective ECM.

Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

Test Drive Confirmation

Note. If conditions in test drive confirmation procedure are not strictly followed, detection of malfunction will not be possible.

1. If using OBD-II scan tool, go to step 3. If using Toyota hand-held tester, connect hand-held tester to Data Link Connector (DLC) No. 3. (Scheme 2) Switch scan tool to CHECK mode and go to next step.
2. Start and warm engine to normal operating temperature with all accessories off. Drive vehicle at 31-40 MPH for 1-3 minutes. Stop vehicle and allow to idle for one minute. Repeat driving and idle part of test 3 times. If malfunction exists, MIL will illuminate.
3. Start and warm engine to normal operating temperature. Drive vehicle at 31-40 MPH for 1-3 minutes. Stop vehicle and allow to idle for one minute. Turn ignition off. Repeat driving and idle part of test. If malfunction exists, MIL will illuminate.

1. If other DTCs are displayed, diagnose and repair those DTCs first and retest system. If only DTC P0130 and/or P0150 are displayed, go to next step.
2. Connect scan tool to Data Link Connector (DLC) No. 3. (Scheme 2) Start engine and increase engine speed to 2500 RPM for approximately 90 seconds. Let engine idle. Using scan tool, monitor each heated oxygen senor No. 1 output voltage. Voltage should alternate repeatedly between less than.4 volt and more than.55 volt. If voltage is as specified, go to step 7. If voltage is not as specified, go to next step.
3. Check for open or short in wiring between ECM and heated oxygen sensors No. 1. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
4. Ensure oil dipstick, oil filler cap, PCV system and all other air induction system components are intact and operating properly. If problem exists, repair as necessary. If problem does not exist, go to next step.
5. Check fuel pressure. See FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - V6 & V8 article. If fuel pressure is not within specification, repair as necessary. If fuel pressure is within specification, go to next step.
6. Check fuel injectors. See FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - V6 & V8 article. If problem exists, repair as necessary. If problem does not exist, replace appropriate heated oxygen sensor No. 1.
7. Perform test drive confirmation, then go to next step. See «TEST DRIVE CONFIRMATION»(/toyota/land-cruiser/100-1998-2002/remont/testing-diagnostics/#engine-control-system-self-diagnostics__test-drive-confirmation).
8. Clear and recheck for DTCs. If DTC P0130 and/or P0150 are displayed again, replace ECM. If neither DTC P0130 nor P0150 are displayed again, problem is intermittent. Check component and ECM connections.

DTC P0133 OR P0153: HEATED OXYGEN SENSOR NO. 1 CIRCUIT SLOW RESPONSE

Note. Bank No. 1 refers to bank which includes cylinder No. 1. Bank No. 2 refers to bank without cylinder No. 1. Heated oxygen sensor No. 1 refers to sensor closest to engine block. DTC P0133 is for bank No. 1, sensor No. 1. DTC P0153 is for bank No. 2, sensor No. 1.

Heated oxygen sensor monitors exhaust gas oxygen content and delivers an input signal to ECM. ECM uses input signal to determine fuel injection system operation. Heated oxygen sensors include a heater. DTC is set when ECM detects a response time of one second or more from heated oxygen sensor to change from rich too lean, or lean too rich when engine is warm and idling. Possible causes are

1. Heated oxygen sensor(s) No. 1 circuit is open or shorted.
2. Defective heated oxygen sensor(s) No. 1.
3. Air induction system malfunction.
4. Improper fuel pressure.
5. Defective fuel injector.
6. Defective ECM.

Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

1. If other DTCs are displayed, diagnose and repair those DTCs first and retest system. If only DTC P0133 and/or P0153 are displayed, go to next step.
2. Connect scan tool to Data Link Connector (DLC) No. 3. (Scheme 2) Start engine and increase engine speed to 2500 RPM for approximately 90 seconds. Let engine idle. Using scan tool, monitor each heated oxygen sensor No. 1 output voltage. Voltage should alternate repeatedly between less than.4 volt and more than.55 volt. If voltage is as specified, go to step 7. If voltage is not as specified, go to next step.
3. Check for open or short in wiring between ECM and heated oxygen sensors No. 1. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
4. Ensure oil dipstick, oil filler cap, PCV system and all other air induction system components are intact and operating properly. If problem exists, repair as necessary. If problem does not exist, go to next step.
5. Check fuel pressure. See FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - V6 & V8 article. If fuel pressure is not within specification, repair as necessary. If fuel pressure is within specification, go to next step.
6. Check fuel injectors. See FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - V6 & V8 article. If problem exists, repair as necessary. If problem does not exist, replace appropriate heated oxygen sensor No. 1.
7. Perform test drive confirmation, then go to next step. See «TEST DRIVE CONFIRMATION»(/toyota/land-cruiser/100-1998-2002/remont/testing-diagnostics/#engine-control-system-self-diagnostics__test-drive-confirmation) under DTC P0130 OR P0150: HEATED OXYGEN SENSOR NO. 1 CIRCUIT.
8. Clear and recheck for DTCs. If DTC P0133 and/or P0153 are displayed again, replace ECM. If neither DTC P0133 nor P0153 are displayed again, problem is intermittent. Check component and ECM connections.

DTC P0135 OR P0155: HEATED OXYGEN SENSOR NO. 1 HEATER CIRCUIT

Note. Bank No. 1 refers to bank which includes cylinder No. 1. Bank No. 2 refers to bank without cylinder No. 1. Heated oxygen sensor No. 1 refers to sensor closest to engine block. Heated oxygen sensor No. 2 refers to sensor farthest from engine block. DTC P0135 is for bank No. 1, sensor No. 1. DTC P0155 is for bank No. 2, sensor No. 1.

Heated oxygen sensor monitors exhaust gas oxygen content and delivers an input signal to ECM. ECM uses input signal to determine fuel injection system operation. Heated oxygen sensors include a heater. DTC is set when heated oxygen sensor heater current draw exceeds 2 amps or heated oxygen sensor heater current draw is .25 amp or less when heater operates. Possible causes are

1. Heated oxygen sensor(s) No. 1 heater circuit is open or shorted.
2. Defective heated oxygen sensor No. 1 heater.
3. Defective ECM.

Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

1. Access ECM behind glove box. Turn ignition on. Using DVOM, backprobe ECM harness connector. If DTC P0135 is set, measure voltage between ground and terminal No. 4 (Red wire) at ECM harness connector E6. If DTC P0155 is set, measure voltage between ground and terminal No. 3 (Yellow wire) at ECM harness connector E6. (Scheme 1) Voltage should be 9-14 volts at each terminal. If voltage is as specified, replace ECM. If voltage is not as specified, go to next step.
2. Disconnect suspect heated oxygen sensor No. 1 harness connector. Measure resistance between terminals B+ (Black/Yellow wire) and HT (Red wire on bank No. 1; Yellow wire on bank No. 2) at heated oxygen sensor connector (component side). (Scheme 4) Resistance should be 11-16 ohms at 68°F (20°C). If resistance is not as specified, replace appropriate heated oxygen sensor No. 1. If resistance is as specified, go to next step.
3. Repair wiring between ECM and appropriate heated oxygen sensor, or between appropriate heated oxygen sensor and EFI main relay. See WIRING DIAGRAMS article.

Scheme 4

DTC P0136 OR P0156: HEATED OXYGEN SENSOR NO. 2 CIRCUIT

Note. Bank No. 1 refers to bank which includes cylinder No. 1. Bank No. 2 refers to bank without cylinder No. 1. Heated oxygen sensor No. 1 refers to sensor closest to engine block. Heated oxygen sensor No. 2 refers to sensor farthest from engine block.

Heated oxygen sensor monitors exhaust gas oxygen content and delivers an input signal to ECM. ECM uses input signal to determine fuel injection system operation. Heated oxygen sensors include a heater. DTC P0136 is set when bank No. 1, sensor No. 2 voltage remains at .4 volt or more, or .5 volt or less during vehicle operation (31 MPH or more), once engine is at normal operating temperature. DTC P0156 is set when bank No. 2, sensor No. 2 voltage remains at .4 volt or more, or .5 volt or less during vehicle operation (31 MPH or more), once engine is at normal operating temperature. Possible cause is

1. Heated oxygen sensor(s) No. 2 circuit is open or shorted.
2. Defective heated oxygen sensor(s) No. 2.

Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

1. If any other DTCs are displayed, diagnose and repair those DTCs first. If only DTC P0136 is displayed, go to next step.
2. Check for open or short in wiring between ECM and appropriate heated oxygen sensor No. 2. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
3. Connect scan tool to Data Link Connector (DLC) No. 3. (Scheme 2) Start and warm engine to normal operating temperature. Monitor appropriate heated oxygen sensor No. 2 output voltage. Snap accelerate engine to about 4000 RPM 3 times. Voltage should fluctuate from less than.4 volt to.5 volt or more. If voltage is as specified, problem is intermittent. Check component and ECM connections. If voltage is not as specified, replace heated oxygen sensor No. 2.

DTC P0141 OR P0161: HEATED OXYGEN SENSOR NO. 2 HEATER CIRCUIT

Note. Bank No. 1 refers to bank which includes cylinder No. 1. Bank No. 2 refers to bank without cylinder No. 1. Heated oxygen sensor No. 1 refers to sensor closest to engine block. Heated oxygen sensor No. 2 refers to sensor farthest from engine block.

Heated oxygen sensor monitors exhaust gas oxygen content and delivers an input signal to ECM. ECM uses input signal to determine fuel injection system operation. Heated oxygen sensors include a heater. DTC P0141 is set when heated oxygen sensor bank No. 1, sensor No. 2 heater current draw exceeds 2 amps or heated oxygen sensor heater current draw is .25 amp or less when heater operates. DTC P0161 is set when heated oxygen sensor bank No. 2, sensor No. 2 heater current draw exceeds 2 amps or heated oxygen sensor heater current draw is .25 amp or less when heater operates. Possible causes are

1. Heated oxygen sensor(s) No. 2 heater circuit is open or shorted.
2. Defective heated oxygen sensor No. 2 heater.
3. Defective ECM.

Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

1. Access ECM behind glove box. Turn ignition on. Using DVOM, backprobe ECM harness connector. If DTC P0141 is set, measure voltage between ground and terminal No. 8 (Blue wire) at ECM harness connector E8. If DTC P0161 is set, measure voltage between ground and terminal No. 7 (Red/Black wire) at ECM harness connector E8. (Scheme 1) Voltage should be 9-14 volts at each terminal. If voltage is as specified, replace ECM. If voltage is not as specified, go to next step.
2. Disconnect suspect heated oxygen sensor No. 2 harness connector. Measure resistance between terminals B+ (Black/Yellow wire) and HT (Blue wire on bank No. 1; Red/Black wire on bank No. 2) at heated oxygen sensor connector (component side). (Scheme 4) Resistance should be 11-16 ohms at 68°F (20°C). If resistance is not as specified, replace appropriate heated oxygen sensor No. 2. If resistance is as specified, go to next step.
3. Repair wiring between ECM and appropriate heated oxygen sensor, or between appropriate heated oxygen sensor and EFI main relay. See WIRING DIAGRAMS article.

DTC P0150: HEATED OXYGEN SENSOR NO. 1 CIRCUIT

See DTC P0130 OR P0150: HEATED OXYGEN SENSOR NO. 1 CIRCUIT .

DTC P0153: HEATED OXYGEN SENSOR NO. 1 CIRCUIT SLOW RESPONSE

See DTC P0133 OR P0153: HEATED OXYGEN SENSOR NO. 1 SLOW RESPONSE .

DTC P0155: HEATED OXYGEN SENSOR NO. 1 HEATER CIRCUIT

See DTC P0135 OR P0155: HEATED OXYGEN SENSOR NO. 1 HEATER CIRCUIT .

DTC P0156: HEATED OXYGEN SENSOR NO. 2 CIRCUIT

See DTC P0136 OR P0156: HEATED OXYGEN SENSOR NO. 2 CIRCUIT .

DTC P0161: HEATED OXYGEN SENSOR NO. 2 HEATER CIRCUIT

See DTC P0141 OR P0161: HEATED OXYGEN SENSOR NO. 2 HEATER CIRCUIT .

DTC P0171 OR P0172: SYSTEM TOO LEAN/RICH

Note. Bank No. 1 refers to bank which includes cylinder No. 1. Bank No. 2 refers to bank without cylinder No. 1. Heated oxygen sensor No. 1 refers to sensor closest to engine block.

Fuel trim refers to feedback compensation value compared against basic injection time. Fuel trim includes short-term and long-term fuel trim.

DTC P0171 is set when fuel trim is driven rich beyond a certain value. Possible causes are

1. Air induction system malfunction.
2. Fuel injector restricted.
3. Defective Mass Airflow (MAF) meter.
4. Defective Engine Coolant Temperature (ECT) sensor.
5. Improper fuel pressure.
6. Exhaust system leak.
7. Heated oxygen sensor (bank No. 1 or 2, sensor No. 1) circuit is open or shorted.
8. Defective heated oxygen sensor (bank No. 1 or 2, sensor No. 1).
9. Defective ECM.

DTC P0172 is set when fuel trim is driven lean beyond a certain value. Possible causes are

1. Fuel injector restricted or leaking.
2. Defective Mass Airflow (MAF) meter.
3. Defective Engine Coolant Temperature (ECT) sensor.
4. Ignition system malfunction.
5. Improper fuel pressure.
6. Exhaust system leak.
7. Heated oxygen sensor (bank No. 1 or 2, sensor No. 1) circuit is open or shorted.
8. Defective heated oxygen sensor (bank No. 1 or 2, sensor No. 1).
9. Defective ECM.

Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

1. Ensure oil dipstick, oil filler cap, PCV system and all other air induction system components are intact and operating properly. If problem exists, repair as necessary. If problem does not exist, go to next step.
2. Check fuel injectors. See FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - V6 & V8 article. If problem exists, repair as necessary. If problem does not exist, go to next step.
3. Check Mass Airflow (MAF) meter and Engine Coolant Temperature (ECT) sensor. See ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - V6 & V8 article. If problem exists, replace appropriate component. If problem does not exist, go to next step.
4. Check spark and ignition system. See IGNITION SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - V6 & V8 article. If problem exists, repair as necessary. If problem does not exist, go to next step.
5. Check fuel pressure. See FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - V6 & V8 article. If fuel pressure is not within specification, repair as necessary. If fuel pressure is within specification, go to next step.
6. Check exhaust system for leaks. If problem exists, repair as necessary. If problem does not exist, go to next step.
7. Connect scan tool to Data Link Connector (DLC) No. 3. (Scheme 2) Start engine and increase engine speed to 2500 RPM for approximately 90 seconds. Let engine idle. Using scan tool, monitor each heated oxygen sensors No. 1 output voltage. Voltage should alternate repeatedly between less than.4 volt and more than.55 volt. If voltage is as specified, go to step 9. If voltage is not as specified, go to next step.
8. Check for open or short in wiring between ECM and heated oxygen sensors No. 1. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, replace appropriate heated oxygen sensor(s) No. 1.
9. Perform test drive confirmation, then go to next step. See «TEST DRIVE CONFIRMATION»(/toyota/land-cruiser/100-1998-2002/remont/testing-diagnostics/#engine-control-system-self-diagnostics__test-drive-confirmation) under DTC P0130 OR P0150: HEATED OXYGEN SENSOR NO. 1 CIRCUIT.
10. Clear and recheck for DTCs. If DTCs P0171 and/or P0172 are displayed again, replace ECM. If neither DTC P0171 nor P0172 are displayed again, go to next step.
11. Vehicle either ran out of fuel or problem is intermittent. Check component and ECM connections.

ECM uses signals provided by crankshaft and camshaft position sensors. If engine speed rate has changed enough to equal a preset number, a misfire is detected and MIL is illuminated. If misfire rate is high enough, and driving conditions will cause catalytic converter damage or overheating, MIL blinks when a misfire is occurring. DTC is set when misfiring of random cylinders is detected during any particular 200 or 1000 revolutions. Possible causes are

1. Open or short in wiring.
2. Poor contact at ECM or component.
3. Blocked, damaged or disconnected vacuum hose(s).
4. Ignition system malfunction.
5. Defective fuel injector(s).
6. Improper fuel pressure.
7. Defective Mass Airflow (MAF) meter.
8. Defective Engine Coolant Temperature (ECT) sensor.
9. Improper engine compression.
10. Improper valve clearance.
11. Improper valve timing.
12. Defective ECM.

When 2 or more codes for misfiring cylinder are recorded repeatedly but no random misfire code is recorded, it indicates misfires were detected and recorded at different times. If misfire cannot be reproduced, reason may be because of driving with lack of fuel, improper fuel, fouled spark plug, etc. Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

1. Connect scan tool to Data Link Connector (DLC) No. 3. (Scheme 2) Record any DTCs and freeze frame data. Switch scan tool to CHECK mode (Toyota hand-held tester only). Drive vehicle several times with engine speed, load and its surrounding range shown with ENGINE SPD, CALC LOAD in freeze frame data or MISFIRE RPM and MISFIRE LOAD in scan tool data list.
2. Drive vehicle at specified engine speeds. See «DRIVING PATTERN»(/toyota/land-cruiser/100-1998-2002/remont/testing-diagnostics/#engine-control-system-self-diagnostics) table. Turn ignition off after symptom is simulated the first time, then repeat test drive again (OBD-II scan tool only). If a misfire is detected, a DTC will set and misfire will be indicated in freeze frame data. Turn ignition off and wait a minimum of 5 seconds. DRIVING PATTERN RPM (1) Minutes Idling 3 1/2 1000 3 2000 1 1/2 3000 1 (1) Minimum specification is given.

1. Check vacuum hoses for leaks, blockage and proper routing. See appropriate illustration in VACUUM DIAGRAMS article. Also, check wiring and connectors for damage or poor connections. If problem exists, repair as necessary and perform «TEST DRIVE CONFIRMATION»(/toyota/land-cruiser/100-1998-2002/remont/testing-diagnostics/#engine-control-system-self-diagnostics). If problem does not exist, go to next step.
2. Check spark and ignition system. See IGNITION SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - V6 & V8 article. If problem exists, repair as necessary. If problem does not exist, go to next step.
3. Access ECM behind glove box. Turn ignition on. Using DVOM, backprobe ECM connector and measure voltage between ground and fuel injector terminals at specified ECM connector. See «IDENTIFYING FUEL INJECTOR TERMINALS»(/toyota/land-cruiser/100-1998-2002/remont/testing-diagnostics/#engine-control-system-self-diagnostics) table. (Scheme 1) If voltage is 9-14 volts at each terminal, go to step 6. If voltage is not 9-14 volts at each terminal, go to next step. IDENTIFYING FUEL INJECTOR TERMINALS Fuel Injector No. Terminal No. Wire Color 1 (1) 5 Yellow 2 (1) 6 Black 3 (2) 1 Blue 4 (2) 2 Red 5 (2) 3 Green 6 (2) 4 Red/Blue 7 (2) 5 White 8 (2) 6 Black/White (1) Terminal are located in ECM harness connector E6. (Scheme 1) (2) Terminals are located in ECM harness connector E5. (Scheme 1)
4. Disconnect fuel injector harness connector at misfiring cylinder. Measure resistance between fuel injector terminals (component side). Resistance should be 13.4-14.2 ohms at 68°F (20°C). If resistance is as specified, go to next step. If resistance is not as specified, replace fuel injector.
5. Check for open or short in wiring between ECM and fuel injector. See WIRING DIAGRAMS article. If problem exists, repair as necessary. If problem does not exist, repair open or short in injector power source circuit. See WIRING DIAGRAMS article.
6. Check fuel pressure. See FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - V6 & V8 article. If fuel pressure is not within specification, repair as necessary. If fuel pressure is within specification, go to next step.
7. Check fuel injectors. See FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - V6 & V8 article. If problem exists, repair as necessary. If problem does not exist, go to next step.
8. Check Mass Airflow (MAF) meter and Engine Coolant Temperature (ECT) sensor. See ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - V6 & V8 article. If problem exists, replace appropriate component. If problem does not exist, go to next step.
9. Check engine compression. See BASIC DIAGNOSTIC PROCEDURES - V6 & V8 article. If engine compression is okay, check valve clearance. See ON-VEHICLE ADJUSTMENTS - V6 & V8 article. If valve clearance is okay, it may be necessary to check valve timing. See appropriate article in ENGINES.

DTCS P0301-P0308: CYLINDERS NO. 1-8 MISFIRE DETECTED

Note. When 2 or more trouble codes for a misfiring cylinder are recorded repeatedly, but DTC P0300 is not recorded, it indicates misfires were detected and stored into ECM memory at different times.

ECM uses signals provided by crankshaft and camshaft position sensors. If engine speed rate has changed enough to equal a preset number, a misfire is detected and MIL is illuminated. If misfire rate is high enough, and driving conditions will cause catalytic converter damage or overheating, MIL blinks when a misfire is occurring. DTC is set during any particular 200 revolutions of engine, misfiring is detected which can cause catalytic converter overheating and/or damage or during any particular 1000 revolutions of engine, misfiring is detected which can cause a deterioration in emission levels. Possible causes are

1. Open or short in wiring.
2. Poor contact at ECM or component.
3. Blocked, damaged or disconnected vacuum hose(s).
4. Ignition system malfunction.
5. Defective fuel injector(s).
6. Improper fuel pressure.
7. Defective Mass Airflow (MAF) meter.
8. Defective Engine Coolant Temperature (ECT) sensor.
9. Improper engine compression.
10. Improper valve clearance.
11. Improper valve timing.
12. Defective ECM.

When 2 or more codes for misfiring cylinder are recorded repeatedly but no random misfire code is recorded, it indicates misfires were detected and recorded at different times. If misfire cannot be reproduced, reason may be because of driving with lack of fuel, improper fuel, fouled spark plug, etc. Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

For diagnosis and repair procedure, see DTC P0300: RANDOM MISFIRE DETECTED .

DTC P0325 OR P0330: KNOCK SENSOR NO. 1 OR 2 CIRCUIT

Knock sensors are located on either side of cylinder block under intake manifold. Knock sensor generates voltage when engine block vibrates due to knocking. DTC P0325 is for bank that includes cylinder No. 1. DTC P0330 is for bank that does not include cylinder No. 1. DTC is set when there is no knock sensor signal to ECM with engine speed 1700-5400 RPM. Possible causes are

1. Knock sensor circuit is open or shorted.
2. Defective or loose knock sensor.
3. Defective ECM.

Normal mode vibration frequency of knock sensors is 8.1 kHz. Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

1. Connect scan tool to Data Link Connector (DLC) No. 3. (Scheme 2) Disconnect EC1 harness connector. EC1 harness connector is a in-line harness connector located at rear of intake manifold. EC1 harness connector is a 3-pin Black connector. Remove, switch and reinstall terminals No. 2 and 3 from male harness connector. (Scheme 5) Connect EC1 harness connector. Turn ignition on. Clear DTCs. Start and warm engine to normal operating temperature. Snap accelerate engine to about 4000 RPM 3 times. Retrieve DTCs. If same DTC is repeated, go to next step. If DTC changed, go to step 3.
2. Check for open or short in wiring between EC1 connector and ECM. If problem exists, repair wiring as necessary. If problem does not exist, replace ECM. Ensure EC1 male connector terminals are returned to their original position.
3. Check for open or short in wiring between EC1 connector and knock sensor(s). To access harness, it may be necessary to remove intake manifold. See KNOCK SENSOR under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 article. If problem exists, repair wiring as necessary. If problem does not exist, replace knock sensor. Ensure EC1 male connector terminals are returned to their original position.

Scheme 5

DTC P0335 OR P1335: CRANKSHAFT POSITION (CKP) SENSOR CIRCUIT

CKP sensor is a pick-up coil mounted next to crankshaft pulley. A 34-tooth signal plate is mounted to crankshaft. DTC P0335 is set if no CKP sensor signal is received by ECM during cranking or no CKP sensor signal is received by ECM with engine speed of 600 RPM or more. DTC P1335 is set if no CKP sensor signal is received by ECM with engine speed of 1000 RPM or more. Possible causes are

1. CKP sensor circuit is open or shorted.
2. Defective CKP sensor.
3. Crankshaft signal plate.
4. Defective ECM.

Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

1. Disconnect CKP sensor harness connector. Measure resistance between CKP sensor terminals (component side). Resistance should be 1630-2740 ohms (cold sensor) or 2065-3225 ohms (hot sensor). If resistance is not as specified, replace CKP sensor. If resistance is as specified, go to next step.
2. Check for open or short in wiring between ECM and CKP sensor. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, remove and inspect CKP sensor. Also inspect signal plate. Replace CKP sensor and/or signal plate as necessary. If both components are okay, replace ECM.

DTC P0340: CAMSHAFT POSITION (CMP) SENSOR CIRCUIT

CMP sensor is a pick-up coil mounted behind timing belt cover, below driver-side camshaft pulley. A one-tooth signal plate is mounted to camshaft. DTC is set when either no cranking or engine running signal is received by ECM from CMP sensor. Possible causes are

1. CMP sensor circuit is open or shorted.
2. Defective CMP sensor.
3. Defective signal plate.
4. Defective ECM.

Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

1. Disconnect CMP sensor harness connector. Measure resistance between CMP sensor terminals (component side). Resistance should be 835-1400 ohms (cold sensor) or 1060-1645 ohms (hot sensor). If resistance is as specified, go to next step. If resistance is not as specified, replace CMP sensor.
2. Check for open or short in wiring between ECM and CMP sensor. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
3. Remove and inspect CMP sensor. Also inspect signal plate. If problem exists, replace CMP sensor and/or signal plate as necessary. If problem does not exist, replace ECM.

DTC P0420 OR P0430: CATALYST SYSTEM EFFICIENCY BELOW THRESHOLD

Note. Bank No. 1 refers to bank which includes cylinder No. 1. Bank No. 2 refers to bank without cylinder No. 1. Heated oxygen sensor No. 1 refers to sensor closest to engine block. Heated oxygen sensor No. 2 refers to sensor farthest from engine block.

ECM compares waveform of heated oxygen sensor No. 1 (located before catalytic converter) with waveform of heated oxygen sensor No. 2 (located after catalytic converter) to determine if catalytic converter performance has deteriorated. If both waveforms change at similar rate, catalytic converter performance has deteriorated. DTC P0420 is set when all heated oxygen sensor bank No. 1, sensors No. 1 and 2 waveforms have same amplitude after vehicle is driven for 5 minutes at 20-50 MPH. DTC P0430 is set when all heated oxygen sensor bank No. 2, sensors No. 1 and 2 waveforms have same amplitude after vehicle is driven for 5 minutes at 20-50 MPH. Possible causes are

1. Defective catalytic converter.
2. Heated oxygen sensor circuit is open or shorted.
3. Defective heated oxygen sensor.

Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

1. If other DTCs are displayed, diagnose and repair those DTCs first and retest system. If only DTC P0420 and/or P0430 is displayed, go to next step.
2. Check exhaust system for leaks. If problem exists, repair as necessary. If problem does not exist, go to next step.
3. Check heated oxygen sensors No. 1 circuits. See «DTC P0130 OR P0150: HEATED OXYGEN SENSOR NO. 1 CIRCUIT»(/toyota/land-cruiser/100-1998-2002/remont/testing-diagnostics/#engine-control-system-self-diagnostics__dtc-p0130-or-p0150-heated-oxygen) . If problem exists, repair as necessary. If problem does not exist, go to next step.
4. Check heated oxygen sensor No. 2 circuits. See «DTC P0136 OR P0156: HEATED OXYGEN SENSOR NO. 2 CIRCUIT»(/toyota/land-cruiser/100-1998-2002/remont/testing-diagnostics/#engine-control-system-self-diagnostics__dtc-p0136-or-p0156-heated-oxygen) . If problem exists, repair as necessary. If problem does not exist, replace catalytic converter.

DTC P0440: EVAPORATIVE EMISSION CONTROL SYSTEM

Note. If DTC P0441, P0446, P0450 or P0451 is output after DTC P0440, perform appropriate test first before performing DTC P0440 test.

Vapor pressure sensor and vapor pressure sensor Vacuum Switching Valve (VSV) are used to detect faults in EVAP system. DTC is set if EVAP system leak is detected or vapor pressure sensor malfunctions. Possible causes are

1. Damaged fuel tank sending unit assembly seal.
2. Fuel tank cap is installed incorrectly.
3. Defective fuel tank cap.
4. Damaged, disconnected or blocked vacuum hose.
5. Damaged fuel tank.
6. Vapor pressure sensor circuit is open or shorted.
7. Defective vapor pressure sensor.
8. Defective charcoal canister.
9. Defective ECM.

Ask customer if fuel cap has been left off, or not been completely tighten recently. This may cause DTC to be set. Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

1. Check for cracks, deformations in fuel tank, charcoal canister and fuel tank filler pipe. Check for disconnected hose and tubes around fuel tank and charcoal canister. If problem exists, repair as necessary. If problem does not exist, go to next step.
2. Check fuel cap. If fuel cap is not an OEM cap, replace cap with an OEM cap. If fuel cap is an OEM cap, go to next step.
3. Check if fuel cap is properly installed. If problem exists, install fuel cap properly. If fuel cap is properly installed, go to next step.
4. Check for damaged fuel cap and gasket. If problem exists, replace fuel cap with OEM cap. If problem does not exist, go to next step.
5. Remove fuel cap. Visually inspect fuel tank filler neck for damage. If problem exists, replace fuel tank filler neck as necessary. If problem does not exist, go to next step.
6. Check vacuum hoses between vapor pressure sensor and vapor pressure sensor VSV, and between vapor pressure sensor VSV and charcoal canister. Check hoses for correct installation, looseness and damage. If problem exists, repair vacuum hoses as necessary. If problem does not exist, go to next step.
7. Check hose and tube between fuel tank and charcoal canister for correct installation and damage. If problem exists, repair as necessary. If problem does not exist, go to next step.
8. Visually inspect charcoal canister for cracks, holes and damage. If problem exists, replace charcoal canister. If problem does not exist, go to next step.
9. Access ECM behind glove box. Turn ignition on. Using DVOM, backprobe ECM harness connector and measure voltage between terminals No. 2 (Blue/Red wire) and No. 18 (Brown/White wire) at ECM harness connector E6. (Scheme 1) If voltage is not 4.5-5.5 volts, replace ECM. If voltage is 4.5-5.5 volts, go to next step.
10. Using DVOM, backprobe ECM harness connector and measure voltage between terminal No. 22 (Blue/Black wire) at ECM harness connector E8 and terminal No. 18 (Brown/White wire) at ECM harness connector E6. (Scheme 1) Disconnect vacuum hose from vapor pressure sensor. Connect a vacuum pump to vapor pressure sensor. Voltage should be 2.9-3.7 volts without vacuum applied and.5 volt or less with 1.18 in. Hg applied. If voltage is as specified, go to step 12. If voltage is not as specified, go to next step.
11. Check for an open or short in wiring between vapor pressure sensor and ECM. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, replace vapor pressure sensor.
12. Connect all previously disconnected components and hoses. Disconnect vacuum hose from port "A" at charcoal canister (vacuum hose from fuel tank-to-charcoal canister). (Scheme 6) Ensure fuel cap is installed properly. Apply approximately.71 psi (.05 kg/cm 2 ) pressure to disconnected vacuum hose. If fuel tank does not hold pressure for a minimum of one minute, repair or replace fuel tank or fuel tank over fill valve as necessary. If fuel tank holds pressure, no fault is indicated at this time. Probable cause of DTC to set was an incorrectly installed fuel cap.

Scheme 6

DTC P0441: INCORRECT EVAP PURGE FLOW, OR DTC P0446: EVAP VENT CONTROL CIRCUIT

Note. If DTC P0441, P0446, P0450 or P0451 is output after DTC P0440, perform appropriate test first before performing DTC P0440 test.

Vapor pressure sensor and vapor pressure sensor Vacuum Switching Valve (VSV) are used to detect faults in EVAP system. DTC is set if EVAP system leak is detected or if there is a malfunction in EVAP VSV, vapor pressure sensor VSV or in vapor pressure sensor. Possible causes are

1. Disconnected or blocked vacuum hose.
2. Vapor pressure sensor circuit is open or shorted.
3. Defective Vapor pressure sensor.
4. EVAP VSV circuit is open or shorted.
5. Defective EVAP VSV.
6. Vapor pressure sensor VSV circuit is open or shorted.
7. Defective vapor pressure sensor VSV.
8. Defective charcoal canister.
9. Defective ECM.

Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

1. Check EVAP VSV, vapor pressure sensor VSV and vapor pressure sensor connectors for damaged pins, corrosion and loose wires. If problem exists, repair connectors as necessary. If problem does not exist, go to next step.
2. Check all EVAP related vacuum hoses for cracks, looseness and correct routing. For proper vacuum hose routing, see appropriate illustration in VACUUM DIAGRAMS article. If problem exists, repair vacuum hoses as necessary. If problem does not exist, go to next step.
3. Access ECM behind glove box. Turn ignition on. Using DVOM, backprobe ECM harness connector and measure voltage between terminals No. 2 (Blue/Red wire) and No. 18 (Brown/White wire) at ECM harness connector E6. (Scheme 1) If voltage is not 4.5-5.5 volts, replace ECM. If voltage is 4.5-5.5 volts, go to next step.
4. Using DVOM, backprobe ECM harness connector and measure voltage between terminal No. 22 (Blue/Black wire) at ECM harness connector E8 and terminal No. 18 (Brown/White wire) at ECM harness connector E6. (Scheme 1) Disconnect vacuum hose from vapor pressure sensor. Connect a vacuum pump to vapor pressure sensor. Voltage should be 2.9-3.7 volts without vacuum applied and.5 volt or less with 1.18 in. Hg applied. If voltage is as specified, go to step 6. If voltage is not as specified, go to next step.
5. Check for open or short in wiring between vapor pressure sensor and ECM. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, replace vapor pressure sensor.
6. Disconnect EVAP VSV vacuum hoses. Apply air pressure to EVAP VSV port "E". (Scheme 7) Air should not flow from port "F". Access ECM behind glove box. Turn ignition on. Using a jumper wire, backprobe between ground and terminal No. 7 (Blue/Black wire) at ECM harness connector E6. (Scheme 1) Air should flow from port "F". If EVAP VSV operates as specified, go to step 10. If EVAP VSV does not operate as specified, go to next step.
7. Check vacuum hose between intake manifold and EVAP VSV, and vacuum hose between EVAP VSV and charcoal canister. If problem exists, replace vacuum hoses as necessary. If problem does not exist, go to next step.
8. Check EVAP VSV. See EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - V6 & V8 article. If problem exists, replace EVAP VSV. If problem does not exist, go to next step.
9. Check for open or short in wiring between EFI main relay and EVAP VSV, and between EVAP VSV and ECM. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, replace ECM.
10. Disconnect vapor pressure sensor VSV vacuum hoses. Apply air pressure to vapor pressure sensor VSV port "E". (Scheme 8) Air should flow from port "G". Access ECM behind glove box. Turn ignition on. Using a jumper wire, backprobe between ground and terminal No. 10 (Blue wire) at ECM harness connector E8. (Scheme 1) Air should flow from port "F". If vapor pressure sensor VSV does not operate as specified, go to next step. If vapor pressure sensor VSV operates as specified, check charcoal canister. Perform appropriate fuel EVAP system test. See FUEL EVAPORATION SYSTEM under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - V6 & V8 article.
11. Check vapor pressure sensor VSV. See EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - V6 & V8 article. If problem exists, replace vapor pressure sensor VSV. If problem does not exist, go to next step.
12. Check for open or short in wiring between EFI main relay and vapor pressure sensor VSV, and between vapor pressure sensor VSV and ECM. See WIRING DIAGRAMS article. If problem exists, repair wiring harness as necessary. If problem does not exist, replace ECM.

Scheme 7

Scheme 8

DTC P0450: EVAP PRESSURE SENSOR CIRCUIT, OR DTC P0451: EVAP PRESSURE SENSOR RANGE/PERFORMANCE

Vapor pressure sensor and vapor pressure sensor Vacuum Switching Valve (VSV) are used to detect faults in EVAP system. DTC is set if vapor pressure sensor malfunctions. Possible causes are

1. Vapor pressure sensor circuit is open or shorted.
2. Defective vapor pressure sensor.
3. Defective ECM.

Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

1. Access ECM behind glove box. Turn ignition on. Using DVOM, backprobe ECM harness connector and measure voltage between terminals No. 2 (Blue/Red wire) and No. 18 (Brown/White wire) at ECM harness connector E6. (Scheme 1) If voltage is not 4.5-5.5 volts, replace ECM. If voltage is 4.5-5.5 volts, go to next step.
2. Using DVOM, backprobe ECM harness connector and measure voltage between terminal No. 22 (Blue/Black wire) at ECM harness connector E8 and terminal No. 18 (Brown/White wire) at ECM harness connector E6. (Scheme 1) Disconnect vacuum hose from vapor pressure sensor. Connect a vacuum pump to vapor pressure sensor. Voltage should be 2.9-3.7 volts without vacuum applied and.5 volt or less with 1.18 in. Hg applied. If voltage is as specified, replace ECM. If voltage is not as specified, go to next step.
3. Check for open or short in wiring between vapor pressure sensor and ECM. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, replace vapor pressure sensor.

DTC P0500: VEHICLE SPEED SENSOR CIRCUIT

Vehicle Speed Sensor (VSS) outputs a 4-pulse signal for every revolution of rotor shaft, which is driven by transaxle output shaft. Signal is sent to instrument cluster to operate speedometer. Instrument cluster then sends signal to ECM. Signal is used by ECM to determine vehicle speed. DTC is set if there is no VSS signal to ECM while vehicle is being driven and park/neutral switch is off. Possible causes are

1. Defective VSS.
2. VSS circuit is open or shorted.
3. Defective instrument cluster.
4. Defective ECM.

Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

1. Test drive vehicle and check operation of speedometer. If speedometer is not operating correctly, repair speedometer as necessary. See appropriate INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. If speedometer is operating correctly, go to next step.
2. Access ECM behind glove box. Raise and support one rear wheel. Turn ignition on. Shift transaxle lever into Neutral. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 15 (Violet wire) at ECM harness connector E8. (Scheme 1) Observe voltage reading while rotating rear wheel. Voltage should pulse between zero volts and 4.5-5.5 volts. If voltage is as specified, replace ECM. If voltage is not as specified, repair open or short in wiring between instrument cluster and ECM. See WIRING DIAGRAMS article.

Idle speed is controlled by Electronic Throttle Control System (ETCS). Description of ETCS components are as follows

1. Throttle motor is used to operate throttle valve.
2. Magnetic clutch is used to connect throttle motor with throttle valve.
3. Throttle position sensor is used to detect opening angle of throttle valve.
4. Accelerator pedal position sensor is used to detect accelerator pedal position.
5. Engine Control Module (ECM) controls ETCS.

DTC is set when idle speed continues to vary greatly from target speed. Possible causes are

1. Defective ETCS.
2. Air induction system malfunction.

Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

1. If any other DTCs are displayed, diagnose and repair those DTCs first and retest. If only DTC P0505 is displayed, go to next step.
2. Ensure oil dipstick, oil filler cap, PCV system and all other air induction system components are intact and operating properly. If problem exists, repair as necessary. If problem does not exist, go to next step.
3. Check Electronic Throttle Control System (ETCS). See THROTTLE BODY under IDLE CONTROL SYSTEMS in SYSTEM & COMPONENT TESTING - V6 & V8 article. Replace components as necessary.

DTC P1120: ACCELERATOR PEDAL POSITION (APP) SENSOR CIRCUIT

Note. If DTCs P0110, P0115, P0120, P0450 and P1120 are output together, check circuit E2 (Brown/White wire) between terminal No. 18 at ECM harness connector E6 and splice E10. Repair as necessary. See WIRING DIAGRAMS article.

Accelerator Pedal Position (APP) sensor is located on throttle body and has 2 variable resistors integral to APP sensor. APP sensor monitors accelerator position and is connected with accelerator pedal by accelerator wire. APP sensor signal voltage (0-5 volts) to ECM changes in proportion to accelerator pedal opening angle. ECM controls throttle motor based on APP sensor voltage signals. If DTC P1120 is present, ECM turns off power to throttle motor and magnetic clutch and throttle valve is fully closed by the return spring. When this occurs, opening angle of throttle valve is controlled by accelerator pedal by means of a throttle cable. DTC is set when ECM detects voltage is out of range on VPA or VPA2 circuits. Possible causes are

1. APP sensor circuit is open or shorted.
2. Defective APP sensor.
3. Defective ECM.

After confirming DTC P1120, use scan tool to access CURRENT DATA to confirm APP sensor voltage with throttle open and closed. If voltage displayed on scan tool for ACCEL POS and ACCEL POS #2 is always zero volts, VC circuit may be open. If voltage displayed on scan tool for ACCEL POS is always zero volts and voltage display for ACCEL POS #2 is 1.8-2.7 volts with fully closed throttle and 4.7-5.1 volts with fully open throttle, VPA circuit may be open or shorted. If voltage displayed on scan tool for ACCEL POS #2 is always zero volts and voltage display for ACCEL POS is .3-.9 volt with fully closed throttle and 3.2-4.8 volts with fully open throttle, VPA2 circuit may be open or shorted. If voltage displayed on scan tool for ACCEL POS and ACCEL POS #2 is always 5 volts, E2 circuit may be open. Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

1. Connect Toyota hand-held tester to Data Link Connector (DLC) No. 3. (Scheme 2) Turn ignition on. Using hand-held tester, monitor APP sensor voltage for VPA and VPA2 circuits. See «ACCELERATOR PEDAL POSITION SENSOR VOLTAGE»(/toyota/land-cruiser/100-1998-2002/remont/testing-diagnostics/#engine-control-system-self-diagnostics) table. If voltage is as specified, replace ECM. If voltage is not as specified, go to next step. ACCELERATOR PEDAL POSITION SENSOR VOLTAGE Accelerator Pedal Volts Depressed VPA Circuit 3.2-4.8 VPA2 Circuit 4.7-5.1 Released VPA Circuit 0.3-0.9 VPA2 Circuit 1.8-2.7
2. Access ECM behind glove box. Turn ignition on. Using DVOM, backprobe ECM harness connector and measure voltage between terminals No. 2 (Blue/Red wire) and No. 18 (Brown/White wire) at ECM harness connector E6. (Scheme 1) If voltage is 4.5-5.5 volts, go to next step. If voltage is not 4.5-5.5 volts, replace ECM.
3. Using DVOM, backprobe ECM harness connector and measure voltage between terminals No. 18 (Brown/White wire) and No. 21 (Red wire) at ECM harness connector E6. With fully closed throttle, voltage should be.3-.9 volt. With fully open throttle, voltage should be 3.2-4.8 volts. Using DVOM, backprobe ECM harness connector and measure voltage between terminals No. 18 (Brown/White wire) and No. 9 (Red/Black wire) at ECM harness connector E6. With fully closed throttle, voltage should be 1.8-2.7 volts. With fully open throttle, voltage should be 4.7-5.1 volts. If voltage readings are as specified, replace ECM. If voltage readings are not as specified, go to next step.
4. Check APP sensor. See THROTTLE BODY under IDLE CONTROL SYSTEMS in SYSTEM & COMPONENT TESTING - V6 & V8 article. If problem exists, replace APP sensor. If problem does not exist, repair open or short in wiring between ECM and APP sensor. See WIRING DIAGRAMS article.

1. Access ECM behind glove box. Turn ignition on. Using DVOM, backprobe ECM harness connector and measure voltage between terminals No. 2 (Blue/Red wire) and No. 18 (Brown/White wire) at ECM harness connector E6. (Scheme 1) If voltage is 4.5-5.5 volts, go to next step. If voltage is not 4.5-5.5 volts, replace ECM.
2. Using DVOM, backprobe ECM harness connector and measure voltage between terminals No. 18 (Brown/White wire) and No. 21 (Red wire) at ECM harness connector E6. With fully closed throttle, voltage should be.3-.9 volt. With fully open throttle, voltage should be 3.2-4.8 volts. Using DVOM, backprobe ECM harness connector and measure voltage between terminals No. 18 (Brown/White wire) and No. 9 (Red/Black wire) at ECM harness connector E6. With fully closed throttle, voltage should be 1.8-2.7 volts. With fully open throttle, voltage should be 4.7-5.1 volts. If voltage readings are as specified, replace ECM. If voltage readings are not as specified, go to next step.
3. Check APP sensor. See THROTTLE BODY under IDLE CONTROL SYSTEMS in SYSTEM & COMPONENT TESTING - V6 & V8 article. If problem exists, replace APP sensor. If problem does not exist, repair open or short in wiring between ECM and APP sensor. See WIRING DIAGRAMS article.

APP sensor is located on throttle body and has 2 variable resistors integral to APP sensor. APP sensor monitors accelerator position and is connected with the accelerator pedal by the accelerator wire. APP sensor signal voltage (0-5 volts) to ECM changes in proportion to accelerator pedal opening angle. ECM turns off power to throttle motor based on APP sensor voltage signals. DTC is set when ECM detects voltage is out of range on VPA circuit or VPA2 circuit. Possible cause is

1. Defective APP sensor.

Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

If any other DTCs are displayed, diagnose and repair those DTCs first and retest. If only DTC P1121 is displayed, replace APP sensor.

DTC P1125: THROTTLE CONTROL MOTOR CIRCUIT

Throttle valve opening angle is detected by Throttle Position (TP) sensor and sends a signal to ECM. ECM then uses this signal to control throttle control motor which opens and closes throttle valve in response to driving conditions. If DTC P1125 is present, ECM turns off power to the throttle motor and magnetic clutch, and throttle valve is fully closed by return spring. When this occurs, opening angle of throttle valve is controlled by accelerator pedal by means of a throttle cable. DTC is set when ECM detects out of range throttle control motor current. Possible causes are

1. Throttle control motor circuit is open or shorted.
2. Defective throttle control motor.
3. Defective ECM.

Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

1. Turn ignition off. Access ECM behind glove box. Connect an oscilloscope by backprobing between terminal No. 17 (Brown wire) at ECM harness connector E6 and terminal No. 8 (Red wire; circuit M+) or No. 7 (White wire; circuit M-) at ECM harness connector E5. Start engine and allow to idle. Observe waveform. (Scheme 9)and (Scheme 10). If waveform is okay, replace ECM. If waveform is not okay, go to next step.
2. Disconnect throttle control motor Gray, 4-pin harness connector. Measure resistance between terminals No. 1 (White wire) and No. 2 (Red wire) at throttle control motor (component side). Resistance should be.3-100.0 ohms at 68°F (20°C). If resistance is as specified, go to next step. If resistance is not as specified, replace throttle control motor.
3. Check for open or short in wiring between throttle control motor and ECM. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, replace ECM.

Scheme 9

Scheme 10

DTC P1126: MAGNETIC CLUTCH CIRCUIT

Magnetic clutch is mounted between throttle control motor and throttle body. Throttle motor opens and closes throttle valve through magnetic clutch. If magnetic clutch is defective, throttle control motor must be replaced. If DTC P1126 is present, ECM turns off power to throttle motor and magnetic clutch, and throttle valve is fully closed by return spring. When this occurs, opening angle of throttle valve is controlled by accelerator pedal by means of a throttle cable. DTC is set when ECM detects out of range throttle control motor current. Possible causes are

1. Magnetic clutch circuit is open or shorted.
2. Defective Magnetic clutch.
3. Defective ECM.

Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

1. If not using Toyota hand-held tester, go to step 3. If using Toyota hand-held tester, go to next step.
2. Connect hand-held tester to Data Link Connector (DLC) No. 3. (Scheme 2) Turn ignition on. Using hand-held tester, read magnetic clutch current value. If reading is.8-1.0 amp, go to step 4. If reading is not.8-1.0 amp, go to step 6.
3. Turn ignition off. Access ECM behind glove box. Connect an oscilloscope by backprobing between terminals No. 24 (Blue wire) and No. 29 (Green wire) at ECM harness connector E5. (Scheme 1) Start engine and allow it to idle. Observe waveform. (Scheme 11) If waveform is not okay, go to next step. If waveform is okay, go to step 6.
4. Disconnect throttle control motor Gray 4-pin harness connector. Measure resistance between terminals No. 3 (Green wire) and No. 4 (Blue wire) at throttle control motor (component side). Resistance should be 4.2-5.2 ohms at 68°F (20°C). If resistance is as specified, go to next step. If resistance is not as specified, replace throttle control motor.
5. Check for open or short in wiring between throttle control motor and ECM. See WIRING DIAGRAM article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
6. Connect all disconnected components. Clear DTC. Start engine. Turn ignition off and wait 3 seconds. Turn ignition on and check for DTCs. If DTC P1126 is not present, replace ECM. If DTC P1126 is present, replace throttle control motor.

Scheme 11

DTC P1127: ELECTRONIC THROTTLE CONTROL SYSTEM ACTUATOR POWER SOURCE CIRCUIT

Battery voltage is supplied to circuit +BM at ECM harness connector E9 at all times. If DTC P1127 is present, ECM turns off power to throttle motor and magnetic clutch, and throttle valve is fully closed by return spring. When this occurs, opening angle of throttle valve is controlled by accelerator pedal by means of a throttle cable. DTC is set when ECM detects an open ETCS power source circuit. Possible causes are

1. ETCS power source circuit is open.
2. Defective ECM.

Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

1. Remove and inspect THROTTLE fuse (15-amp) from left-side engine compartment fuse block. If fuse is okay, go to next step. If fuse is blown, check for cause of fuse to blow. See WIRING DIAGRAMS article. Repair as necessary and retest.
2. Access ECM behind glove box. Using DVOM, backprobe and measure voltage between ground and terminal No. 7 (Yellow/Black wire) at ECM harness connector E9. (Scheme 1) If voltage is 9-14 volts, replace ECM. If voltage is not 9-14 volts, repair open in power source circuit. See WIRING DIAGRAMS article.

Throttle valve opening angle is detected by Throttle Position (TP) sensor and sends a signal to the ECM. ECM then uses this signal to control throttle control motor which opens and closes throttle valve in response to driving conditions. If DTC P1128 is present, ECM turns off power to throttle motor and magnetic clutch, and throttle valve is fully closed by return spring. When this occurs, opening angle of throttle valve is controlled by accelerator pedal by means of a throttle cable. DTC is set when ECM detects a locked throttle control motor. Possible causes are

1. Defective throttle body assembly.
2. Defective throttle control motor.
3. Defective ECM.

Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

1. Turn ignition off. Disconnect throttle control motor Gray, 4-pin harness connector. Measure resistance between terminals No. 1 (White wire) and No. 2 (Red wire) at throttle control motor (component side). Resistance should be .3-100.0 ohms at 68°F (20°C). If resistance is as specified, go to next step. If resistance is not as specified, replace throttle control motor.
2. Remove air inlet hose from throttle body. Visually inspect throttle body for carbon build-up or foreign material holding throttle valve open. If problem exists, repair as necessary. If problem does not exist, replace throttle body.

DTC P1129: ELECTRONIC THROTTLE CONTROL SYSTEM CIRCUIT

Throttle valve opening angle is detected by Throttle Position (TP) sensor and sends a signal to ECM. ECM then uses this signal to control throttle control motor which opens and closes throttle valve in response to driving conditions. If DTC P1129 is present, ECM turns off power to throttle motor and magnetic clutch, and throttle valve is fully closed by return spring. When this occurs, opening angle of throttle valve is controlled by accelerator pedal by means of a throttle cable. DTC is set when throttle opening angle varies greatly from target throttle opening angle. Possible causes are

1. Throttle control motor circuit is open.
2. Defective Throttle body.
3. Defective ECM.

Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

Replace ECM. Clear DTCs and retest. Retrieve DTCs. If DTC P1129 is present, replace throttle body and retest.

DTC P1200: FUEL PUMP RELAY/ECU CIRCUIT

Fuel pump is controlled in one of 3 speeds by fuel pump Electronic Control Unit (ECU) depending upon engine load and engine speed. Fuel pump ECU is controlled by ECM. Under high engine load and high engine speed, ECM applies about 3.8 volts to fuel pump ECU. Fuel pump ECU then applies battery voltage to fuel pump, resulting in high speed fuel pump operation. Under medium engine load and low engine speed, ECM applies about 2.5 volts to fuel pump ECU. Fuel pump ECU then applies about 10 volts to fuel pump, resulting in medium speed fuel pump operation. With engine idling or under light load, ECM applies about 1.3 volts to fuel pump ECU. Fuel pump ECU then applies about 8.5 volts to fuel pump, resulting in low speed fuel pump operation. DTC is set when ECM detects an open or short in a fuel pump ECU circuit with engine speed of 1000 RPM or less. Possible causes are

1. Fuel pump ECU circuit is open or shorted.
2. Defective fuel pump ECU.
3. Defective ECM power source circuit.
4. Defective fuel pump.
5. Defective ECM.

Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

1. Check fuel pump operation. See FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - V6 & V8 article. If problem exists, go to next step. If problem does not exist, go to step 7.
2. Disconnect fuel pump ECU 10-pin harness connector. Turn ignition on. Measure voltage between ground and terminal No. 10 (Black/Yellow wire) at fuel pump ECU harness connector. (Scheme 12) If voltage is 9-14 volts, go to next step. If voltage is not 9-14 volts, check for open or short in Black/Yellow wire between EFI main relay and fuel pump ECU. See WIRING DIAGRAMS article.
3. With ignition switch in START position, measure voltage between terminals No. 5 (White/Black wire) and No. 8 (Green/White wire) at fuel pump ECU harness connector. If voltage is 3.3-4.3 volts, go to step 5. If voltage is not 3.3-4.3 volts, go to next step.
4. Check for open or short in FPC circuit between ECM and fuel pump ECU. Also check fuel pump ECU ground circuit. See WIRING DIAGRAMS article. If problem exists, repair as necessary. If problem does not exist, replace ECM.
5. Check fuel pump resistance. See FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - V6 & V8 article. If resistance is not as specified, replace fuel pump. If resistance is as specified, go to next step.
6. Check for open or short in wiring between fuel pump and fuel pump ECU. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, replace fuel pump.
7. Check for open or short in Green/Red wire between terminal No. 4 at ECM harness connector E9 and terminal No. 9 at fuel pump ECU harness connector. If problem exists, repair wiring as necessary. If problem does not exist, replace ECM.

Scheme 12

DTC P1300: IGNITOR NO. 1 CIRCUIT

Direct Ignition System (DIS) is a 1-cylinder ignition system that ignites one cylinder with one ignition coil. Ignitor is integral to ignition coil. ECM determines ignition timing and outputs a ignition signal (IGT) for each cylinder. Based on IGT signals, power transistors in ignitor cut off current to primary coil in ignition coil, causing ignition coil to fire spark plug. After delivering a command to turn off primary circuit on IGT wire, ECM monitors IGF circuit to ensure primary switching occurred. DTC P1300 is for ignition coil No. 1 and is set when there is no IGF signal to ECM during engine operation. Possible causes are

1. IGF1 or IGT1 circuit from ignitor to ECM is open or shorted.
2. Defective ignition coil/ignitor No. 1.
3. Defective ECM.

Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

1. Check for spark at misfiring cylinder. See IGNITION SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - V6 & V8 article. If spark exists, go to next step. If spark does not exist, go to step 4.
2. Check for open or short in Black wire between terminal No. 11 at ECM harness connector E5 and ignition coil/ignitor No. 1. Also, check for open or short in Black/White wire between terminal No. 27 at ECM harness connector E5 and ignition coil/ignitor No. 1. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
3. Disconnect ignition coil/ignitor No. 1 harness connector. Access ECM behind glove box. Turn ignition on. Using DVOM, backprobe at ECM harness connector and measure voltage between ground and terminal No. 27 (Black/White wire) at ECM harness connector E5. (Scheme 1) If voltage is 4.5-5.5 volts, replace ignition coil/ignitor No. 1. If voltage is not 4.5-5.5 volts, replace ECM.
4. Check for open or short in Black wire between terminal No. 11 at ECM harness connector E5 and ignition coil/ignitor No. 1. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
5. Access ECM behind glove box. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 11 (Black wire) at ECM harness connector E5 while cranking engine. (Scheme 1) If voltage is.1-4.5 volts, go to next step. If voltage is not.1-4.5 volts, replace ECM.
6. Disconnect ignition coil/ignitor No. 1 harness connector. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 11 (Black wire) at ECM harness connector E5 while cranking engine. If voltage is.1-4.5 volts, go to next step. If voltage is not.1-4.5 volts, replace ECM.
7. Turn ignition on. Measure voltage between ground and terminal No. 1 (Black/Red wire) at ignition coil/ignitor No. 1 harness connector. (Scheme 13) If voltage is 9-14 volts, go to next step. If voltage is not 9-14 volts, check and repair ignition coil/ignitor No. 1 power source circuit. See WIRING DIAGRAMS article.
8. Check for open or short in wiring between ground and ignition coil/ignitor No. 1. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
9. Check EFI main relay. See MOTORS & RELAYS in SYSTEM & COMPONENT TESTING - V6 & V8 article. If problem exists, replace EFI main relay. If problem does not exist, replace ignition coil/ignitor No. 1.

Scheme 13

DTC P1305: IGNITOR NO. 2 CIRCUIT

Direct Ignition System (DIS) is a 1-cylinder ignition system that ignites one cylinder with one ignition coil. Ignitor is integral to ignition coil. ECM determines ignition timing and outputs a ignition signal (IGT) for each cylinder. Based on IGT signals, power transistors in the ignitor cut off current to primary coil in ignition coil, causing ignition coil to fire spark plug. After delivering a command to turn off primary circuit on IGT wire, ECM monitors IGF circuit to ensure primary switching occurred. DTC P1305 is for ignition coil No. 2 and is set when there is no IGF signal to ECM during engine operation. Possible causes are

1. IGF2 or IGT2 circuit from ignitor to ECM is open or shorted.
2. Defective ignition coil/ignitor No. 2.
3. Defective ECM.

Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

1. Check for spark at misfiring cylinder. See IGNITION SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - V6 & V8 article. If spark exists, go to next step. If spark does not exist, go to step 4.
2. Check for open or short in Red wire between terminal No. 12 at ECM harness connector E5 and ignition coil/ignitor No. 2. Also, check for open or short in Black/Red wire between terminal No. 28 at ECM harness connector E5 and ignition coil/ignitor No. 2. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
3. Disconnect ignition coil/ignitor No. 2 harness connector. Access ECM behind glove box. Turn ignition on. Using DVOM, backprobe at ECM harness connector and measure voltage between ground and terminal No. 28 (Black/Red wire) at ECM harness connector E5. (Scheme 1) If voltage is 4.5-5.5 volts, replace ignition coil/ignitor No. 2. If voltage is not 4.5-5.5 volts, replace ECM.
4. Check for open or short in Red wire between terminal No. 12 at ECM harness connector E5 and ignition coil/ignitor No. 2. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
5. Access ECM behind glove box. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 12 (Red wire) at ECM harness connector E5 while cranking engine. (Scheme 1) If voltage is.1-4.5 volts, go to next step. If voltage is not.1-4.5 volts, replace ECM.
6. Disconnect ignition coil/ignitor No. 2 harness connector. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 12 (Red wire) at ECM harness connector E5 while cranking engine. If voltage is.1-4.5 volts, go to next step. If voltage is not.1-4.5 volts, replace ECM.
7. Turn ignition on. Measure voltage between ground and terminal No. 1 (Black/Red wire) at ignition coil/ignitor No. 2 harness connector. (Scheme 13) If voltage is 9-14 volts, go to next step. If voltage is not 9-14 volts, check and repair ignition coil/ignitor No. 2 power source circuit. See WIRING DIAGRAMS article.
8. Check for open or short in wiring between ground and ignition coil/ignitor No. 2. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
9. Check EFI main relay. See MOTORS & RELAYS in SYSTEM & COMPONENT TESTING - V6 & V8 article. If problem exists, replace EFI main relay. If problem does not exist, replace ignition coil/ignitor No. 2.

DTC P1310: IGNITOR NO. 3 CIRCUIT

Direct Ignition System (DIS) is a 1-cylinder ignition system that ignites one cylinder with one ignition coil. Ignitor is integral to ignition coil. ECM determines ignition timing and outputs a ignition signal (IGT) for each cylinder. Based on IGT signals, power transistors in the ignitor cut off current to primary coil in ignition coil, causing ignition coil to fire spark plug. After delivering a command to turn off primary circuit on IGT wire, ECM monitors IGF circuit to ensure primary switching occurred. DTC P1310 is for ignition coil No. 3 and is set when there is no IGF signal to ECM during engine operation. Possible causes are

1. IGF2 or IGT3 circuit from ignitor to ECM is open or shorted.
2. Defective ignition coil/ignitor No. 3.
3. Defective ECM.

Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

1. Check for spark at misfiring cylinder. See IGNITION SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - V6 & V8 article. If spark exists, go to next step. If spark does not exist, go to step 4.
2. Check for open or short in Blue wire between terminal No. 13 at ECM harness connector E5 and ignition coil/ignitor No. 3. Also, check for open or short in Black/Red wire between terminal No. 28 at ECM harness connector E5 and ignition coil/ignitor No. 3. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
3. Disconnect ignition coil/ignitor No. 3 harness connector. Access ECM behind glove box. Turn ignition on. Using DVOM, backprobe at ECM harness connector and measure voltage between ground and terminal No. 28 (Black/Red wire) at ECM harness connector E5. (Scheme 1) If voltage is 4.5-5.5 volts, replace ignition coil/ignitor No. 3. If voltage is not 4.5-5.5 volts, replace ECM.
4. Check for open or short in Blue wire between terminal No. 13 at ECM harness connector E5 and ignition coil/ignitor No. 3. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
5. Access ECM behind glove box. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 13 (Blue wire) at ECM harness connector E5 while cranking engine. (Scheme 1) If voltage is.1-4.5 volts, go to next step. If voltage is not.1-4.5 volts, replace ECM.
6. Disconnect ignition coil/ignitor No. 3 harness connector. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 13 (Blue wire) at ECM harness connector E5 while cranking engine. If voltage is.1-4.5 volts, go to next step. If voltage is not.1-4.5 volts, replace ECM.
7. Turn ignition on. Measure voltage between ground and terminal No. 1 (Black/Red wire) at ignition coil/ignitor No. 3 harness connector. (Scheme 13) If voltage is 9-14 volts, go to next step. If voltage is not 9-14 volts, check and repair ignition coil/ignitor No. 3 power source circuit. See WIRING DIAGRAMS article.
8. Check for open or short in wiring between ground and ignition coil/ignitor No. 3. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
9. Check EFI main relay. See MOTORS & RELAYS in SYSTEM & COMPONENT TESTING - V6 & V8 article. If problem exists, replace EFI main relay. If problem does not exist, replace ignition coil/ignitor No. 3.

DTC P1315: IGNITOR NO. 4 CIRCUIT

Direct Ignition System (DIS) is a 1-cylinder ignition system that ignites one cylinder with one ignition coil. Ignitor is integral to ignition coil. ECM determines ignition timing and outputs a ignition signal (IGT) for each cylinder. Based on IGT signals, power transistors in the ignitor cut off current to primary coil in ignition coil, causing ignition coil to fire spark plug. After delivering a command to turn off primary circuit on IGT wire, ECM monitors IGF circuit to ensure primary switching occurred. DTC P1315 is for ignition coil No. 4 and is set when there is no IGF signal to ECM during engine operation. Possible causes are

1. IGF1 or IGT4 circuit from ignitor to ECM is open or shorted.
2. Defective ignition coil/ignitor No. 4.
3. Defective ECM.

Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

1. Check for spark at misfiring cylinder. See IGNITION SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - V6 & V8 article. If spark exists, go to next step. If spark does not exist, go to step 4.
2. Check for open or short in Green wire between terminal No. 14 at ECM harness connector E5 and ignition coil/ignitor No. 4. Also, check for open or short in Black/White wire between terminal No. 27 at ECM harness connector E5 and ignition coil/ignitor No. 4. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
3. Disconnect ignition coil/ignitor No. 4 harness connector. Access ECM behind glove box. Turn ignition on. Using DVOM, backprobe at ECM harness connector and measure voltage between ground and terminal No. 27 (Black/White wire) at ECM harness connector E5. (Scheme 1) If voltage is 4.5-5.5 volts, replace ignition coil/ignitor No. 4. If voltage is not 4.5-5.5 volts, replace ECM.
4. Check for open or short in Green wire between terminal No. 14 at ECM harness connector E5 and ignition coil/ignitor No. 4. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
5. Access ECM behind glove box. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 14 (Green wire) at ECM harness connector E5 while cranking engine. (Scheme 1) If voltage is.1-4.5 volts, go to next step. If voltage is not.1-4.5 volts, replace ECM.
6. Disconnect ignition coil/ignitor No. 4 harness connector. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 14 (Green wire) at ECM harness connector E5 while cranking engine. If voltage is.1-4.5 volts, go to next step. If voltage is not.1-4.5 volts, replace ECM.
7. Turn ignition on. Measure voltage between ground and terminal No. 1 (Black/Red wire) at ignition coil/ignitor No. 4 harness connector. (Scheme 13) If voltage is 9-14 volts, go to next step. If voltage is not 9-14 volts, check and repair ignition coil/ignitor No. 4 power source circuit. See WIRING DIAGRAMS article.
8. Check for open or short in wiring between ground and ignition coil/ignitor No. 4. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
9. Check EFI main relay. See MOTORS & RELAYS in SYSTEM & COMPONENT TESTING - V6 & V8 article. If problem exists, replace EFI main relay. If problem does not exist, replace ignition coil/ignitor No. 4.

DTC P1320: IGNITOR NO. 5 CIRCUIT

Direct Ignition System (DIS) is a 1-cylinder ignition system that ignites one cylinder with one ignition coil. Ignitor is integral to ignition coil. ECM determines ignition timing and outputs a ignition signal (IGT) for each cylinder. Based on IGT signals, power transistors in the ignitor cut off current to primary coil in ignition coil, causing ignition coil to fire spark plug. After delivering a command to turn off primary circuit on IGT wire, ECM monitors IGF circuit to ensure primary switching occurred. DTC P1320 is for ignition coil No. 5 and is set when there is no IGF signal to ECM during engine operation. Possible causes are

1. IGF2 or IGT5 circuit from ignitor to ECM is open or shorted.
2. Defective ignition coil/ignitor No. 5.
3. Defective ECM.

Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

1. Check for spark at misfiring cylinder. See IGNITION SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - V6 & V8 article. If spark exists, go to next step. If spark does not exist, go to step 4.
2. Check for open or short in Yellow wire between terminal No. 15 at ECM harness connector E5 and ignition coil/ignitor No. 5. Also, check for open or short in Black/Red wire between terminal No. 28 at ECM harness connector E5 and ignition coil/ignitor No. 5. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
3. Disconnect ignition coil/ignitor No. 5 harness connector. Access ECM behind glove box. Turn ignition on. Using DVOM, backprobe at ECM harness connector and measure voltage between ground and terminal No. 28 (Black/Red wire) at ECM harness connector E5. (Scheme 1) If voltage is 4.5-5.5 volts, replace ignition coil/ignitor No. 5. If voltage is not 4.5-5.5 volts, replace ECM.
4. Check for open or short in Yellow wire between terminal No. 15 at ECM harness connector E5 and ignition coil/ignitor No. 5. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
5. Access ECM behind glove box. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 15 (Yellow wire) at ECM harness connector E5 while cranking engine. (Scheme 1) If voltage is.1-4.5 volts, go to next step. If voltage is not.1-4.5 volts, replace ECM.
6. Disconnect ignition coil/ignitor No. 5 harness connector. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 15 (Yellow wire) at ECM harness connector E5 while cranking engine. If voltage is.1-4.5 volts, go to next step. If voltage is not.1-4.5 volts, replace ECM.
7. Turn ignition on. Measure voltage between ground and terminal No. 1 (Black/Red wire) at ignition coil/ignitor No. 5 harness connector. (Scheme 13) If voltage is 9-14 volts, go to next step. If voltage is not 9-14 volts, check and repair ignition coil/ignitor No. 5 power source circuit. See WIRING DIAGRAMS article.
8. Check for open or short in wiring between ground and ignition coil/ignitor No. 5. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
9. Check EFI main relay. See MOTORS & RELAYS in SYSTEM & COMPONENT TESTING - V6 & V8 article. If problem exists, replace EFI main relay. If problem does not exist, replace ignition coil/ignitor No. 5.

DTC P1325: IGNITOR NO. 6 CIRCUIT

Direct Ignition System (DIS) is a 1-cylinder ignition system that ignites one cylinder with one ignition coil. Ignitor is integral to ignition coil. ECM determines ignition timing and outputs a ignition signal (IGT) for each cylinder. Based on IGT signals, power transistors in the ignitor cut off current to primary coil in ignition coil, causing ignition coil to fire spark plug. After delivering a command to turn off primary circuit on IGT wire, ECM monitors IGF circuit to ensure primary switching occurred. DTC P1325 is for ignition coil No. 6 and is set when there is no IGF signal to ECM during engine operation. Possible causes are

1. IGF1 or IGT6 circuit from ignitor to ECM is open or shorted.
2. Defective ignition coil/ignitor No. 6.
3. Defective ECM.

Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

1. Check for spark at misfiring cylinder. See IGNITION SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - V6 & V8 article. If spark exists, go to next step. If spark does not exist, go to step 4.
2. Check for open or short in Black/Yellow wire between terminal No. 16 at ECM harness connector E5 and ignition coil/ignitor No. 6. Also, check for open or short in Black/White wire between terminal No. 27 at ECM harness connector E5 and ignition coil/ignitor No. 6. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
3. Disconnect ignition coil/ignitor No. 6 harness connector. Access ECM behind glove box. Turn ignition on. Using DVOM, backprobe at ECM harness connector and measure voltage between ground and terminal No. 27 (Black/White wire) at ECM harness connector E5. (Scheme 1) If voltage is 4.5-5.5 volts, replace ignition coil/ignitor No. 6. If voltage is not 4.5-5.5 volts, replace ECM.
4. Check for open or short in Black/Yellow wire between terminal No. 16 at ECM harness connector E5 and ignition coil/ignitor No. 6. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
5. Access ECM behind glove box. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 16 (Black/Yellow wire) at ECM harness connector E5 while cranking engine. (Scheme 1) If voltage is.1-4.5 volts, go to next step. If voltage is not.1-4.5 volts, replace ECM.
6. Disconnect ignition coil/ignitor No. 6 harness connector. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 16 (Black/Yellow wire) at ECM harness connector E5 while cranking engine. If voltage is.1-4.5 volts, go to next step. If voltage is not.1-4.5 volts, replace ECM.
7. Turn ignition on. Measure voltage between ground and terminal No. 1 (Black/Red wire) at ignition coil/ignitor No. 6 harness connector. (Scheme 13) If voltage is 9-14 volts, go to next step. If voltage is not 9-14 volts, check and repair ignition coil/ignitor No. 6 power source circuit. See WIRING DIAGRAMS article.
8. Check for open or short in wiring between ground and ignition coil/ignitor No. 6. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
9. Check EFI main relay. See MOTORS & RELAYS in SYSTEM & COMPONENT TESTING - V6 & V8 article. If problem exists, replace EFI main relay. If problem does not exist, replace ignition coil/ignitor No. 6.

DTC P1330: IGNITOR NO. 7 CIRCUIT

Direct Ignition System (DIS) is a 1-cylinder ignition system that ignites one cylinder with one ignition coil. Ignitor is integral to ignition coil. ECM determines ignition timing and outputs a ignition signal (IGT) for each cylinder. Based on IGT signals, power transistors in the ignitor cut off current to primary coil in ignition coil, causing ignition coil to fire spark plug. After delivering a command to turn off primary circuit on IGT wire, ECM monitors IGF circuit to ensure primary switching occurred. DTC P1330 is for ignition coil No. 7 and is set when there is no IGF signal to ECM during engine operation. Possible causes are

1. IGF1 or IGT7 circuit from ignitor to ECM is open or shorted.
2. Defective ignition coil/ignitor No. 7.
3. Defective ECM.

Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

1. Check for spark at misfiring cylinder. See IGNITION SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - V6 & V8 article. If spark exists, go to next step. If spark does not exist, go to step 4.
2. Check for open or short in Black/Blue wire between terminal No. 25 at ECM harness connector E5 and ignition coil/ignitor No. 7. Also, check for open or short in Black/White wire between terminal No. 27 at ECM harness connector E5 and ignition coil/ignitor No. 7. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
3. Disconnect ignition coil/ignitor No. 7 harness connector. Access ECM behind glove box. Turn ignition on. Using DVOM, backprobe at ECM harness connector and measure voltage between ground and terminal No. 27 (Black/White wire) at ECM harness connector E5. (Scheme 1) If voltage is 4.5-5.5 volts, replace ignition coil/ignitor No. 7. If voltage is not 4.5-5.5 volts, replace ECM.
4. Check for open or short in Black/Blue wire between terminal No. 25 at ECM harness connector E5 and ignition coil/ignitor No. 7. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
5. Access ECM behind glove box. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 25 (Black/Blue wire) at ECM harness connector E5 while cranking engine. (Scheme 1) If voltage is.1-4.5 volts, go to next step. If voltage is not.1-4.5 volts, replace ECM.
6. Disconnect ignition coil/ignitor No. 7 harness connector. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 25 (Black/Blue wire) at ECM harness connector E5 while cranking engine. If voltage is.1-4.5 volts, go to next step. If voltage is not.1-4.5 volts, replace ECM.
7. Turn ignition on. Measure voltage between ground and terminal No. 1 (Black/Red wire) at ignition coil/ignitor No. 7 harness connector. (Scheme 13) If voltage is 9-14 volts, go to next step. If voltage is not 9-14 volts, check and repair ignition coil/ignitor No. 7 power source circuit. See WIRING DIAGRAMS article.
8. Check for open or short in wiring between ground and ignition coil/ignitor No. 7. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
9. Check EFI main relay. See MOTORS & RELAYS in SYSTEM & COMPONENT TESTING - V6 & V8 article. If problem exists, replace EFI main relay. If problem does not exist, replace ignition coil/ignitor No. 7.

DTC P1335: CRANKSHAFT POSITION (CKP) SENSOR CIRCUIT

For testing procedures, see DTC P0335 OR P1335: CRANKSHAFT POSITION (CKP) SENSOR CIRCUIT .

DTC P1340: IGNITOR NO. 8 CIRCUIT

Direct Ignition System (DIS) is a 1-cylinder ignition system that ignites one cylinder with one ignition coil. Ignitor is integral to ignition coil. ECM determines ignition timing and outputs a ignition signal (IGT) for each cylinder. Based on IGT signals, power transistors in the ignitor cuts off current to primary coil in ignition coil, causing ignition coil to fire spark plug. After delivering a command to turn off primary circuit on IGT wire, ECM monitors IGF circuit to ensure primary switching occurred. DTC P1340 is for ignition coil No. 8 and is set when there is no IGF signal to ECM during engine operation. Possible causes are

1. IGF2 or IGT8 circuit from ignitor to ECM is open or shorted.
2. Defective ignition coil/ignitor No. 8.
3. Defective ECM.

Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

1. Check for spark at misfiring cylinder. See IGNITION SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - V6 & V8 article. If spark is exists, go to next step. If spark is not exist, go to step 4.
2. Check for open or short in Blue/Black wire between terminal No. 26 at ECM harness connector E5 and ignition coil/ignitor No. 8. Also, check for open or short in Black/Red wire between terminal No. 28 at ECM harness connector E5 and ignition coil/ignitor No. 8. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
3. Disconnect ignition coil/ignitor No. 8 harness connector. Access ECM behind glove box. Turn ignition on. Using DVOM, backprobe at ECM harness connector and measure voltage between ground and terminal No. 28 (Black/Red wire) at ECM harness connector E5. (Scheme 1) If voltage is 4.5-5.5 volts, replace ignition coil/ignitor No. 8. If voltage is not 4.5-5.5 volts, replace ECM.
4. Check for open or short in Blue/Black wire between terminal No. 26 at ECM harness connector E5 and ignition coil/ignitor No. 8. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
5. Access ECM behind glove box. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 26 (Blue/Black wire) at ECM harness connector E5 while cranking engine. (Scheme 1) If voltage is.1-4.5 volts, go to next step. If voltage is not.1-4.5 volts, replace ECM.
6. Disconnect ignition coil/ignitor No. 8 harness connector. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 26 (Blue/Black wire) at ECM harness connector E5 while cranking engine. If voltage is.1-4.5 volts, go to next step. If voltage is not.1-4.5 volts, replace ECM.
7. Turn ignition on. Measure voltage between ground and terminal No. 1 (Black/Red wire) at ignition coil/ignitor No. 8 harness connector. (Scheme 13) If voltage is 9-14 volts, go to next step. If voltage is not 9-14 volts, check and repair ignition coil/ignitor No. 8 power source circuit. See WIRING DIAGRAMS article.
8. Check for open or short in wiring between ground and ignition coil/ignitor No. 8. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
9. Check EFI main relay. See MOTORS & RELAYS in SYSTEM & COMPONENT TESTING - V6 & V8 article. If problem exists, replace EFI main relay. If problem does not exist, replace ignition coil/ignitor No. 8.

DTC P1520: STOPLIGHT SWITCH SIGNAL CIRCUIT (A/T ONLY)

Stoplight switch signal is used to detect when brakes have been applied. ECM uses this signal to control fuel cut-off engine speed. DTC is set if stoplight switch does not turn off when vehicle is being driven. Possible causes are

1. Stoplight switch signal circuit is shorted.
2. Defective stoplight switch.
3. Defective ECM.

Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

1. Check stoplight operation. If stoplights do not operate properly, repair as necessary and retest system. See EXTERIOR LIGHTS article in ACCESSORIES & EQUIPMENT. If stoplights operate properly, go to next step.
2. Access ECM behind glove box. Turn ignition on. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 6 (Green/White wire) at ECM harness connector E8. (Scheme 1) Voltage should be 7.5-14.0 volts with brake pedal depressed and less than 1.5 volts with brake pedal released. If voltage is not as specified, go to next step. If voltage is as specified, problem is intermittent. Check component and ECM connections.
3. Check for short in wiring between ECM and stoplight switch. If problem exists, repair wiring as necessary. If problem does not exist, replace ECM.

DTC P1600: ECM BATT CIRCUIT

Battery voltage is supplied to ECM BATT terminal (constant). DTC is set when open in back-up power source is detected. Possible causes are

1. Back-up power source circuit is open.
2. Defective ECM.

Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

1. Turn ignition off. Access ECM behind glove box. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 1 (Black/Red wire) at ECM harness connector E9. (Scheme 1) If voltage is 9-14 volts, replace ECM. If voltage is not 9-14 volts, go to next step.
2. Remove and inspect EFI fuse. EFI fuse is located in engine compartment fuse box. If fuse is blown, check for short to ground in wiring between EFI fuse and ECM. See WIRING DIAGRAMS article. Repair as necessary and replace fuse. If fuse is okay, check for open in wiring between EFI fuse and ECM. Repair as necessary.

DTC P1633: ECM MALFUNCTION (ELECTRONIC THROTTLE CONTROL SYSTEM CIRCUIT)

Throttle valve opening angle is detected by Throttle Position (TP) sensor and sends a signal to ECM. ECM then uses this signal to control throttle control motor which opens and closes throttle valve in response to driving conditions. Possible cause is

1. Defective ECM.

If DTC P1633 is present, replace ECM and retest.

DTC P1780: PARK/NEUTRAL POSITION (PNP) SWITCH CIRCUIT (A/T ONLY)

PNP switch sends a signal to ECM when transaxle is in Neutral or Park. This signal is used for air/fuel correction and for idle speed control. DTC is set when 2 or more switches are on simultaneously for "R", "N", "2" and "L" position, or ECM is receiving an ON signal from PNP switch when vehicle is being operated for more than 30 seconds at 50 MPH or more (2000-5000 RPM). Possible causes are

1. PNP switch circuit is shorted.
2. Defective PNP switch.
3. Defective ECM.

Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

Note. Toyota hand-held tester can be used to confirm PNP switch signal from CURRENT DATA.

1. Access ECM behind glove box. Turn ignition on. Using DVOM, backprobe ECM harness connector and measure voltage between ground and specified terminal at ECM harness connector E8 with shift lever in appropriate position. See «PARK/NEUTRAL POSITION SWITCH VOLTAGE»(/toyota/land-cruiser/100-1998-2002/remont/testing-diagnostics/#engine-control-system-self-diagnostics) table. (Scheme 1) If voltage is as specified, replace ECM. If voltage is not as specified, go to next step. PARK/NEUTRAL POSITION SWITCH VOLTAGE Shift Lever Position Terminal No. Volts Park & Neutral 2 Zero 3 Zero 4 Zero 19 Zero 20 Zero Reverse 2 (1) 7.5-14 3 Zero 4 Zero 19 Zero 20 (1) 9-14 Drive 2 Zero 3 Zero 4 Zero 19 7.5-14 20 9-14 2 2 Zero 3 7.5-14 4 Zero 19 Zero 20 9-14 Low 2 Zero 3 Zero 4 7.5-14 19 Zero 20 9-14 (1) Voltage may be slightly less due to lighting of reverse lights.
2. Disconnect PNP switch harness connector. Check continuity between appropriate PNP switch terminals (component side) with shift lever in appropriate position. See «PARK/NEUTRAL POSITION SWITCH CONTINUITY»(/toyota/land-cruiser/100-1998-2002/remont/testing-diagnostics/#engine-control-system-self-diagnostics) table. (Scheme 14) If problem exists, replace PNP switch. If problem does not exist, go to next step. PARK/NEUTRAL POSITION SWITCH CONTINUITY Shift Lever Position Continuity Between Terminals No. Park 1 & 3; 6 & 9 Reverse 2 & 3 Neutral 3 & 5; 6 & 9 Drive 3 & 7 2 3 & 4 Low 3 & 8
3. Check wiring between battery and PNP switch and between PNP switch and ECM. See WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, replace ECM.

Scheme 14

See also:
• TWO-TRIP DETECTION LOGIC
• P0100
• P0101
• P0110
• P0115
• P0116
• P0120
• P0125
• P0130
• P0133
• P0135
• P0136
• P0141
• P0150
• P0153
• P0155
• P0156
• P0161
• P0171
• P0301
• P0325
• P0335
• P0340
• P0420
• P0440
• P0441
• P0450
• P0500
• P1120
• P1125
• P1126
• P1127
• P1129
• P1200
• P1300
• P1305
• P1310
• P1315
• P1320
• P1325
• P1330
• P1335
• P1340
• P1520
• P1600
• P1633
• P1780
• TEST DRIVE CONFIRMATION