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Engine Control System (Diagnostics - Introduction): Other Scion xD I

Testing & Diagnostics 8 illustrations ~2120 words

DEFINITION OF TERMS

TermsDefinition
Monitor DescriptionDescription of what ECM monitors and how it detects malfunctions (monitoring purpose and details).
Related DTCsGroup of diagnostic trouble codes that are output by ECM based on same malfunction detection logic.
Typical Enabling ConditionPreconditions that allow ECM to detect malfunctions. With all preconditions satisfied, ECM sets DTC when monitored value(s) exceeds malfunction threshold(s).
Sequence of OperationOrder of monitor priority, applied if multiple sensors and components involved in single malfunction detection process. Each sensor and component monitored in turn, when previous detection operation completed.
Required Sensor/ComponentsSensors and components used by ECM to detect each malfunction.
Frequency of OperationNumber of times ECM checks for each malfunction during each driving cycle. "Once per driving cycle" means ECM only performs checks for that malfunction once during single driving cycle. "Continuous" means ECM performs checks for that malfunction whenever enabling conditions met.
DurationMinimum time for which ECM must detect continuous deviation in monitored value(s) in order to set DTC. Timing begins when Typical Enabling Conditions met.
Malfunction ThresholdsValue beyond which ECM determines malfunctions exist and sets DTCs.
MIL OperationTiming of MIL illumination after malfunction detected. "Immediate" means ECM illuminates MIL as soon as malfunction detected. "2 driving cycle" means ECM illuminates MIL if same malfunction detected second time during next sequential driving cycle.

Scheme 23

Scheme 23: ILLUSTRATION

Scheme 24

Scheme 24: ILLUSTRATION

Scheme 25

Scheme 25: ILLUSTRATION

Scheme 26

Scheme 26: SYSTEM DIAGRAM

Scheme 27

Scheme 27

Scheme 28

Scheme 28

Scheme 29

Scheme 29

CHECK FOR INTERMITTENT PROBLEMS

HINT

Inspect the vehicle's ECM using check mode. Intermittent problems are easier to detect with the Techstream when the ECM is in check mode. In check mode, the ECM uses 1 trip detection logic, which is more sensitive to malfunctions than normal mode (default), which uses 2 trip detection logic.

  1. Clear DTCs. Refer to «DTC CHECK / CLEAR»(ref-388734-S06424090862011031100000) .
  2. Switch the ECM from normal mode to check mode using the Techstream. Refer to «CHECK MODE PROCEDURE»(ref-388734-S35382545492011031100000) .
  3. Perform a simulation test. Refer to «HOW TO PROCEED WITH TROUBLESHOOTING»(ref-388639-S13424876092011031100000) .
  4. Check and wiggle the harness(es), connector(s) and terminal(s). Refer to «HOW TO PROCEED WITH TROUBLESHOOTING»(ref-388639-S13424876092011031100000) .

REGISTRATION

Note. The Vehicle Identification Number (VIN) must be input into the replacement ECM.

HINT

The VIN is in the form of a 17-digit alphanumeric vehicle identification number. The Techstream is required to register the VIN.

  1. DESCRIPTION HINT: This registration information consists of two parts: Read VIN and Write VIN. Read VIN: This process allows the VIN stored in the ECM to be read in order to confirm that the two VINs, provided with the vehicle and stored in the vehicle's ECM, are the same. Write VIN: This process allows the VIN to be input into the ECM. If the ECM is changed, or the ECM VIN and vehicle VIN do not match, the VIN can be registered, or overwritten in the ECM by following this procedure.
  2. READ VIN Confirm the vehicle VIN. Connect the Techstream to the DLC3. Turn the ignition switch to ON. Turn the Techstream on. Enter the following menus: Powertrain / Engine and ECT / Utility / VIN / VIN Read.
  3. WRITE VIN Confirm the vehicle VIN. Connect the Techstream to the DLC3. Turn the ignition switch to ON. Turn the Techstream on. Enter the following menus: Powertrain / Engine and ECT / Utility / VIN / VIN Write.

CHECKING MONITOR STATUS

The purpose of the monitor result (mode 06) is to allow access to the results for on-board diagnostic monitoring tests of specific components/systems that are not continuously monitored. Examples are the catalyst, evaporative emission (EVAP) and thermostat.

The monitor result allows the OBD II scan tool to display the monitor status, test value, minimum test limit and maximum test limit. These data are displayed after the vehicle has been driven to run the monitor.

When the test value is not between the minimum test limit and maximum test limit, the ECM (PCM) interprets this as a malfunction. When the component is not malfunctioning, if the difference of the test value and test limit is very small, the component will malfunction in the near future.

Perform the following instruction to view the monitor status. Although this instruction references the Lexus/Toyota diagnostic tester, it can be checked using a generic OBD II scan tool. Refer to your scan tool operator's manual for specific procedures.

  1. PERFORM MONITOR DRIVE PATTERN Connect the Techstream to the DLC3. Turn the ignition switch to ON. Turn the Techstream on. Clear DTCs. Refer to «DTC CHECK / CLEAR»(ref-388734-S06424090862011031100000) . Run the vehicle in accordance with the applicable drive pattern described in READINESS MONITOR DRIVE PATTERN. Refer to «READINESS MONITOR DRIVE PATTERN»(ref-388734-S30606484762011031100000) . Do not turn the ignition switch to OFF. NOTE: The test results will be lost if the ignition switch is turned to OFF.
  2. ACCESS MONITOR RESULT Enter the following menus: Powertrain / Engine and ECT / Monitor / Result. The monitor status appears after the component name. Pass: The component is functioning normally. Fail: The component is malfunctioning. Confirm that the component is either Pass or Fail. Select the component and press ENTER. The accuracy test value appears if the monitor status is either Pass or Fail.
  3. CHECK COMPONENT STATUS Compare the test value with the minimum test limit and maximum test limit. If the test value is between the minimum test limit and maximum test limit, the component is functioning normally. If not, the component is malfunctioning. The test value is usually significantly higher or lower than the test limit. If the test value is on the borderline of the test limit, the component will malfunction in the near future. HINT: The monitor result might on rare occasions be Pass even if the malfunction indicator lamp (MIL) is illuminated. This indicates the system malfunctioned on a previous driving cycle. This might be caused by an intermittent problem.
  4. MONITOR RESULT INFORMATION If you use a generic scan tool, multiply the value by the scaling value listed below. A/F SENSOR (SENSOR 1) Monitor ID Test ID Scaling Unit Description $01 $8E Multiply by 0.001 V A/F sensor deterioration level $01 $91 Multiply by 0.004 mA A/F sensor current HO2 SENSOR (SENSOR 2) Monitor ID Test ID Scaling Unit Description $02 $07 Multiply by 0.001 V Minimum sensor voltage $02 $08 Multiply by 0.001 V Maximum sensor voltage $02 $8B Multiply by 0.001 Seconds 0.35 - 0.2 V sensor switch time $02 $8D Multiply by 0.001 Seconds Duration that sensor voltage drops to 0.2 V during fuel cut $02 $8F Multiply by 0.0003 g Maximum oxygen storage capacity CATALYST Monitor ID Test ID Scaling Unit Description $21 $A9 Multiply by 0.0003 No dimension Oxygen storage capacity of catalyst ADVANCE/RETARDED INTAKE SIDE Monitor ID Test ID Scaling Unit Description $35 $81 Multiply by 0.01 Second Forced movement of oil control valve time ADVANCE/RETARDED EXHAUST SIDE Monitor ID Test ID Scaling Unit Description $35 $85 Multiply by 0.01 Second Forced movement of oil control valve time REAR OXYGEN SENSOR HEATER Monitor ID Test ID Scaling Unit Description $42 $91 Multiply by 0.001 Ohm Oxygen sensor heater resistance bank 1 sensor 2 EVAP Monitor ID Test ID Scaling Unit Description $3D $C9 Multiply by 0.001 kPa Test value for small leak (P0456) $3D $CA Multiply by 0.001 kPa Test value for gross leak (P0455) $3D $CB Multiply by 0.001 kPa Test value for leak detection pump stuck OFF (P2401) $3D $CD Multiply by 0.001 kPa Test value for leak detection pump stuck ON (P2402) $3D $CE Multiply by 0.001 kPa Test value for vent valve stuck OFF (P2420) $3D $CF Multiply by 0.001 kPa Test value for vent valve stuck ON (P2419) $3D $D0 Multiply by 0.001 kPa Test value for reference orifice low flow (P043E) $3D $D1 Multiply by 0.001 kPa Test value for reference orifice high flow (P043F) $3D $D4 Multiply by 0.001 kPa Test value for purge VSV stuck closed (P0441) $3D $D5 Multiply by 0.001 kPa Test value for purge VSV stuck open (P0441) $3D $D7 Multiply by 0.001 kPa Test value for purge flow insufficient (P0441) MISFIRE Monitor ID Test ID Scaling Unit Description $A1 $0B Multiply by 1 Time Total EWMA misfire count of all cylinders in last ten driving cycles EWMA: Exponential Weighted Moving Average $A1 $0C Multiply by 1 Time When ignition switch is ON, total misfire count of all cylinders in last driving cycle is displayed. While engine is running, total misfire count of all cylinders in current driving cycle is displayed. $A2 $0B Multiply by 1 Time Total EWMA misfire count of cylinder 1 in last ten driving cycles $A2 $0C Multiply by 1 Time When ignition switch is ON, total misfire count of cylinder 1 in last driving cycle is displayed. While engine is running, total misfire count of cylinder 1 in current driving cycle is displayed. $A3 $0B Multiply by 1 Time Total EWMA misfire count of cylinder 2 in last ten driving cycles $A3 $0C Multiply by 1 Time When ignition switch is ON, total misfire count of cylinder 2 in last driving cycle is displayed. While engine is running, total misfire count of cylinder 2 in current driving cycle is displayed. $A4 $0B Multiply by 1 Time Total EWMA misfire count of cylinder 3 in last ten driving cycles $A4 $0C Multiply by 1 Time When ignition switch is ON, total misfire count of cylinder 3 in last driving cycle is displayed. While engine is running, total misfire count of cylinder 3 in current driving cycle is displayed. $A5 $0B Multiply by 1 Time Total EWMA misfire count of cylinder 4 in last ten driving cycles $A5 $0C Multiply by 1 Time When ignition switch is ON, total misfire count of cylinder 4 in last driving cycle is displayed. While engine is running, total misfire count of cylinder 4 in current driving cycle is displayed.

READINESS MONITOR DRIVE PATTERN

  1. PURPOSE OF READINESS TESTS The On-Board Diagnostic (OBD II) system is designed to monitor the performance of emission related components, and indicate any detected abnormalities with DTCs (Diagnostic Trouble Codes). Since various components need to be monitored during different driving conditions, the OBD II system is designed to run separate monitoring programs called Readiness Monitors. To view the status, Enter the following menus: Powertrain / Engine and ECT / Monitor / Status2. When the Readiness Monitor status reads Complete, the necessary conditions have been met for running the performance tests for that Readiness Monitor. A generic OBD II scan tool can also be used to view the Readiness Monitor status. HINT: Many state Inspection and Maintenance (I/M) programs require a vehicle's Readiness Monitor status to show Complete before beginning emission tests. The Readiness Monitor will be reset to Incomplete if: The ECM has lost battery power or blown a fuse. DTCs have been cleared. The conditions for running the Readiness Monitor have not been met. If the Readiness Monitor status shows Incomplete, follow the appropriate Readiness Monitor Drive Pattern to change the status to Complete. WARNING: Strictly observe posted speed limits, traffic laws, and road conditions when performing these drive patterns. NOTE: These drive patterns represent the fastest method of satisfying all conditions necessary to achieve complete status for each specific Readiness Monitor. In the event of a drive pattern being interrupted (possibly due to factors such as traffic conditions), the drive pattern can be resumed. In most cases, the Readiness Monitor will still achieve complete status upon completion of the drive pattern. To ensure completion of the Readiness Monitors, avoid sudden changes in vehicle load and speed (driving up and down hills and/or sudden acceleration).
  2. CATALYST MONITOR (ACTIVE AIR-FUEL RATIO CONTROL TYPE) Refer to Confirmation Driving Pattern [P0420]. Refer to «CONFIRMATION DRIVING PATTERN»(ref-388737-S34600523542011031100000) .
  3. VVT SYSTEM MONITOR Refer to Confirmation Driving Pattern [P0011]. Refer to «CONFIRMATION DRIVING PATTERN»(ref-388738-S24346145812011031100000) . Refer to Confirmation Driving Pattern [P0014]. Refer to «CONFIRMATION DRIVING PATTERN»(ref-388738-S12109230852011031100000) .
  4. EVAP SYSTEM MONITOR (KEY OFF TYPE) Refer to Confirmation Driving Pattern [EVAP System]. Refer to «CONFIRMATION DRIVING PATTERN»(ref-388739-S27213837192011031100000) .
  5. AIR-FUEL RATIO (A/F) AND HEATED OXYGEN (HO2) SENSOR MONITORS (ACTIVE AIR-FUEL RATIO CONTROL TYPE) Refer to Confirmation Driving Pattern [P0136]. Refer to «CONFIRMATION DRIVING PATTERN»(ref-388738-S14121339052011031100000) . Refer to Confirmation Driving Pattern [P2195]. Refer to «CONFIRMATION DRIVING PATTERN»(ref-388739-S18777418492011031100000) .
  6. AIR-FUEL RATIO (A/F) AND HEATED OXYGEN (HO2) SENSOR HEATER MONITORS (FRONT A/F AND REAR HO2 SENSOR TYPE) Refer to Confirmation Driving Pattern [P0031]. Refer to «CONFIRMATION DRIVING PATTERN»(ref-388738-S06730259632011031100000) . Refer to Confirmation Driving Pattern [P0037]. Refer to «CONFIRMATION DRIVING PATTERN»(ref-388738-S42491724042011031100000) .

CHECK MODE PROCEDURE

Compared to normal mode, check mode is more sensitive to malfunctions. Therefore, check mode can detect the malfunctions that cannot be detected in normal mode.

Note. All the stored DTCs and freeze frame data are erased if: 1) the ECM is changed from normal mode to check mode or vice-versa; or 2) the ignition switch is turned from ON to ACC or OFF while in check mode. Before changing modes, always check and note any DTCs and freeze frame data.

Scheme 30

Scheme 30: CHECK MODE PROCEDURE
  1. CHECK MODE PROCEDURE Check and ensure the following conditions: Battery voltage 11 V or more. Throttle valve fully closed. Transmission in the P or N (neutral) position. A/C switch OFF. Turn the ignition switch to OFF. Connect the Techstream to the DLC3. Turn the ignition switch to ON. Turn the Techstream on. Enter the following menus: Powertrain / Engine and ECT / Utility / Check Mode. Switch the ECM from normal mode to check mode. Make sure the MIL flashes as shown in the illustration. Start the engine. Make sure the MIL turns OFF. Simulate the conditions of the malfunction described by the customer. Check DTCs and freeze frame data using the tester.

FAIL-SAFE CHART

If any of the following DTCs are set, the ECM enters fail-safe mode to allow the vehicle to be driven temporarily or stops fuel injection.

DTCComponentFail-Safe OperationFail-Safe Deactivation Condition
P0031 P0032 P101DAir Fuel Ratio (A/F) Sensor HeaterECM turns off A/F sensor heaterIgnition switch OFF
P0037 P0038 P102DHeated Oxygen (HO2) Sensor HeaterECM turns off HO2 sensor heaterIgnition switch OFF
P0102 P0103Mass Air Flow (MAF) MeterECM calculates ignition timing according to engine speed and throttle valve positionPass condition detected
P0112 P0113Intake Air Temperature (IAT) SensorECM estimates IAT to be 20°C (68°F)Pass condition detected
P0115 P0117 P0118Engine Coolant Temperature (ECT) SensorECM estimates ECT to be 80°C (176°F)Pass condition detected
P0120 P0121 P0122 P0123 P0220 P0222 P0223 P0604 P0606 P060A P060D P060E P0657 P1607 P2102 P2103 P2111 P2112 P2118 P2119 P2135Electronic Throttle Control System (ETCS)ECM cuts off throttle actuator current and throttle valve returned to 6° throttle position by return spring ECM then adjusts engine output by controlling fuel injection (intermittent fuel-cut) and ignition timing in accordance with accelerator pedal opening angle, to allow vehicle to continue at minimal speed *1Pass condition detected and then ignition switch turned OFF
P0300 P0301 P0302 P0303 P0304 *2Fuel injector Electronic Throttle Control System (ETCS)When catalyst damage misfire occurs (MIL blinking), following fail-safe operation performed for catalyst overheat malfunction prevention Under low load and low engine speed Fuel cut performed on malfunctioning cylinder Under high load and high engine speed Throttle valve opening angle control is performed All cylinder fuel cut or malfunction cylinder fuel cutPass condition detected and then ignition switch turned OFF
P0327 P0328Knock SensorECM sets ignition timing to maximum retardIgnition switch OFF
P0351 to P0354IgniterECM cuts fuelPass condition detected
P2120 P2121 P2122 P2123 P2125 P2127 P2128 P2138Accelerator Pedal Position (APP) SensorAPP sensor has 2 sensor circuits: Main and Sub. If either of circuits malfunctions, ECM controls engine using other circuit. If both of circuits malfunction, ECM regards accelerator pedal as being released. As a result, throttle valve is closed and engine idles.Pass condition detected and then ignition switch turned OFF

HINT

  1. *1: The vehicle can be driven slowly when the accelerator pedal is depressed firmly and slowly. If the accelerator pedal is depressed quickly, the vehicle may speed up and slow down erratically.
  2. *2: Misfire related fail-safe operations occur when catalyst overheat malfunctions occur.