TWO-TRIP DETECTION LOGIC
When a malfunction initially occurs, trouble code will be temporarily stored in ECM memory, but MIL on instrument panel will not illuminate. The second time malfunction is detected, MIL on instrument panel will illuminate, provided ignition is turned off and then back on after first malfunction was detected. This is referred to as the Two-Trip Detection Logic.
Note. When road testing vehicle in Check Mode, the Two Trip Detection Logic will not function. Also, MIL will illuminate the first time a malfunction is detected.
DATA LINK CONNECTOR
OBD-II regulations (SAE J-1850) standardizes DLC configurations. DLC-3 is located in fuse box at lower left of instrument panel. The terminal arrangement of connector complies with SAE J-1962 regulations. (Scheme 48)
Scheme 48
FREEZE-FRAME DATA
The ECM records engine operating condition (fuel system, calculated load, coolant temperature, fuel trim (mixture), engine speed, vehicle speed, etc.) with 1st malfunction ONLY. The information is ONLY for the 1st recorded failure, no matter if more than one code has been recorded. The freeze-frame data is only updated when all codes have been cleared, or a misfire or fuel-trim malfunction has occurred.
Normal Mode Code Retrieval
- Connect scan tool to DLC-3. (Scheme 48) Turn ignition on. Turn on scan tool. Retrieve any trouble codes stored in memory following scan tool instructions. See «TROUBLE CODE IDENTIFICATION»(ref-21645-S31820517372001010300000) table.
- Codes recorded may not have illuminated MIL. When certain malfunctions or trouble codes initially occur, they will be temporarily stored in ECM memory, but MIL will not illuminate.
- The second time malfunction or trouble code is detected, MIL will illuminate, provided ignition is turned off and then back on after malfunction or trouble code was first detected. This process is referred to as Two Trip Detection Logic and only applies to most trouble codes.
- Also record freeze-frame data. If using Toyota scan tool, ensure tool is in normal mode. CHECK MODE will erase all codes.
Note. When scan tester is switched from normal mode to check mode, all trouble codes and freeze-frame data will be erased. DO NOT switch modes until all trouble codes and freeze-frame data are recorded.
Check Mode Code Retrieval (Toyota Scan Tester Only)
- Ensure vehicle battery is fully charged. Apply parking brake. Shift transaxle into Neutral (M/T) or Park (A/T). Turn A/C and all accessories off. Ensure throttle is in idle position.
- Connect scan tester to DLC-3. (Scheme 48) Turn ignition on with engine off. Turn scan tester on.
- Switch scan tester from normal mode to check mode. Check mode is operational if MIL on instrument panel flashes. Start engine. Ensure MIL goes off. Try to simulate conditions of driveability complaint described by customer. NOTE: DO NOT turn ignition off until trouble codes and freeze-frame data are recorded. If ignition is turned off, scan tester will switch from check mode to normal mode and all trouble codes and freeze-frame data will be erased.
- Record any trouble codes and freeze-frame data displayed for system diagnosis. See «TROUBLE CODE IDENTIFICATION»(ref-21645-S31820517372001010300000) table. Information may be useful for determining conditions in which the malfunction occurs.
SUMMARY
If no hard trouble codes are present, driveability symptoms exist or intermittent trouble codes exist, see TESTS W/O CODES article for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.) or intermittent procedures.
CODE P0100 - MASS AIRFLOW SENSOR CIRCUIT
| CAUTION | If ECM replacement is instructed in following testing, always ensure ECM harness connector and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. |
Condition
Following conditions continue with engine speed of 900 RPM or less
- Closed throttle position switch in ON position.
- Mass Airflow (MAF) sensor output is 2.2 volts or less.
CODE P0110 - INTAKE AIR TEMPERATURE SENSOR CIRCUIT
| CAUTION | If ECM replacement is instructed in following testing, always ensure ECM harness connector and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. |
CODE P0115 - COOLANT TEMPERATURE SENSOR CIRCUIT
| CAUTION | If ECM replacement is instructed in following testing, always ensure ECM harness connector and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. |
Code is set when sensor temperature is 86°F (30°C) or less for at least 20 minutes of engine operation. Possible causes are
- Coolant Temperature Sensor (CTS).
- Cooling system.
CODE P0120 - THROTTLE POSITION SENSOR CIRCUIT MALFUNCTION
| CAUTION | If ECM replacement is instructed in following testing, always ensure ECM harness connector and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. |
Code is set when ECM consistently detects more than 2 volts from VTA circuit and closed throttle position switch is on. Possible cause is Throttle Position (TP) sensor.
CODE P0125 - INSUFFICIENT COOLANT TEMPERATURE FOR CLOSED LOOP FUEL CONTROL
| CAUTION | If ECM replacement is instructed in following testing, always ensure ECM harness connector and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. |
CODE P0130 - HEATED OXYGEN SENSOR (RIGHT SIDE, NO. 1) CIRCUIT
| CAUTION | If ECM replacement is instructed in following testing, always ensure ECM harness connector and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. |
Code is set when right side oxygen sensor voltage remains at .40-.55 volt during idle, once engine is at normal operating temperature. Possible causes are
- Heated oxygen sensor.
- Fuel trim malfunction.
Note. Oxygen sensor located nearest radiator is referred to as left oxygen sensor. see scheme 7
Code is set when ECM detects a response time of one second or more from sensor to change from rich to lean, or lean to rich. Possible cause is heated oxygen sensor.
Note. Oxygen sensor located nearest radiator is referred to as left oxygen sensor. see scheme 7
CODE P0135 - HEATED OXYGEN SENSOR (RIGHT SIDE, NO. 1) CIRCUIT
| CAUTION | If ECM replacement is instructed in following testing, always ensure ECM harness connector and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. |
Code is set when either of the following conditions is present
- Sensor heater current draw exceeds 2 amps, or voltage drop of circuit exceeds 5 volts.
- Sensor heater current draw is .25 amp or less.
Possible causes are
- Heated oxygen sensor open or short circuit.
- Heated oxygen sensor heater.
- ECM.
Note. Oxygen sensor located nearest radiator is referred to as left oxygen sensor. see scheme 7
Code is set when right side oxygen sensor voltage remains at .40-.55 volt during vehicle operation (31 MPH or more), once engine is at normal operating temperature. Possibly caused by heated oxygen sensor.
Note. Oxygen sensor located behind catalytic converter is referred to as right oxygen sensor, No. 2.
CODE P0141 - HEATED OXYGEN SENSOR (RIGHT SIDE, NO. 2) CIRCUIT
See CODE P0135 - HEATED OXYGEN SENSOR (RIGHT SIDE, NO. 1) CIRCUIT .
CODE P0150 - HEATED OXYGEN SENSOR (LEFT SIDE) CIRCUIT
See CODE P0130 - HEATED OXYGEN SENSOR (RIGHT SIDE, NO. 1) CIRCUIT .
Code is set when ECM detects a response time of one second or more from sensor to change from rich to lean, or lean to rich. Possible cause is heated oxygen sensor.
Note. Oxygen sensor located nearest radiator is referred to as left oxygen sensor.
CODE P0155 - HEATED OXYGEN SENSOR (LEFT SIDE) CIRCUIT
See CODE P0135 - HEATED OXYGEN SENSOR (RIGHT SIDE, NO. 1) CIRCUIT .
CODE P0170 - FUEL TRIM MALFUNCTION
| CAUTION | If ECM replacement is instructed in following testing, always ensure ECM harness connector and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. |
CODES P0301-P0306 - CYLINDERS NO. 1-6 MISFIRE DETECTED
Note. When 2 or more codes for a misfiring cylinder are recorded repeatedly, but Code P0300 is not recorded, it indicates that misfires were detected and stored into ECM memory at different times.
Two conditions can cause code to set. These are
- During any particular 200 revolutions of engine, misfiring is detected which can cause catalytic converter overheating and/or damage.
- During any particular 1000 revolutions of engine, misfiring is detected which can cause a deterioration in emission levels.
For possible causes, see CODE P0300 - RANDOM MISFIRE DETECTED .
CODES P0325 & P0330 - KNOCK SENSORS NO. 1 & 2 CIRCUIT
| CAUTION | If ECM replacement is instructed in following testing, always ensure ECM harness connector and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. |
CODE P0335 - CRANKSHAFT POSITION SENSOR CIRCUIT
| CAUTION | If ECM replacement is instructed in following testing, always ensure ECM harness connector and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. |
CODE P0340 - CAMSHAFT POSITION SENSOR CIRCUIT
| CAUTION | If ECM replacement is instructed in following testing, always ensure ECM harness connector and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. |
CODE P0401 - INSUFFICIENT EXHAUST GAS RECIRCULATION FLOW DETECTED
| CAUTION | If ECM replacement is instructed in following testing, always ensure ECM harness connector and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. |
CODE P0402 - EXCESSIVE EXHAUST GAS RECIRCULATION FLOW DETECTED
| CAUTION | If ECM replacement is instructed in following testing, always ensure ECM harness connector and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. |
CODE P0441 - EVAPORATIVE EMISSION CONTROL SYSTEM, INCORRECT PURGE FLOW (CALIFORNIA EMISSION MODELS ONLY)
| CAUTION | If ECM replacement is instructed in following testing, always ensure ECM harness connector and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. |
CODE P0500 - VEHICLE SPEED SENSOR MALFUNCTION
| CAUTION | If ECM replacement is instructed in following testing, always ensure ECM harness connector and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. |
CODE P0505 - IDLE AIR CONTROL SYSTEM MALFUNCTION
| CAUTION | If ECM replacement is instructed in following testing, always ensure ECM harness connector and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. |
CODE P0510 - CLOSED THROTTLE POSITION SWITCH MALFUNCTION
| CAUTION | If ECM replacement is instructed in following testing, always ensure ECM harness connector and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. |
CODE P1300 - IGNITOR CIRCUIT MALFUNCTION
| CAUTION | If ECM replacement is instructed in following testing, always ensure ECM harness connector and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. |
CODE P1500 - STARTER SIGNAL CIRCUIT MALFUNCTION
| CAUTION | If ECM replacement is instructed in following testing, always ensure ECM harness connector and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. |
CODE P1600 - ECM BATT MALFUNCTION
| CAUTION | If ECM replacement is instructed in following testing, always ensure ECM harness connector and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. |
CODE P1605 - KNOCK CONTROL CPU MALFUNCTION
| CAUTION | If ECM replacement is instructed in following testing, always ensure ECM harness connector and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. |
CODE P1780 - PARK/NEUTRAL POSITION SWITCH
| CAUTION | If ECM replacement is instructed in following testing, always ensure ECM harness connector and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. |
Note. Toyota scan tester can be used to confirm PNP switch.