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Advanced Scan Tool Diagnostics Steve Zack Jim Wilson. CAN Controller Area Network. Controller Area Network. Primary purpose is to network vehicle control module using a Standard protocol Reduces redundant sensors and or wiring (multiplexing) reducing weight and increasing reliability
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Controller Area Network • Primary purpose is to network vehicle control module using a Standard protocol • Reduces redundant sensors and or wiring (multiplexing) • reducing weight and increasing reliability • Using serial data bus to transfer data • Allowing for reliable multiple processor instead of one unreliable large one
OBD II Modes • MODE 1 • Request For Current Power train Diagnostic Data • MODE 2 • Request for Freeze Frame Data • MODE 3 • Request for the Emission Related Trouble Codes
OBD II Modes • MODE 4 • Request to Clear/Reset Diagnostic Trouble Codes • MODE 5 • Request Oxygen Sensor Monitoring Test Results
OBD II Mode 6 and 7 • MODE 6 • Request for the latest on-board monitoring test results for non-continuous test results • MODE 7 • Request for the latest on-board monitoring test results for continuous monitoring systems
Mode 8 and 9 • Mode 8 • Request control of a On-Board System, Test, or Component • Mode 9 • Request for Vehicle Identification Number and Calibration IDs
Mode 6 Example EGR Monitor • The PCM will compare test from a Hexadecimal chart
EGR Monitor • Before the monitor test begins the following must be completed • Engine at operating temperature • 3 minutes since start up • RPM at specified spec • MAP voltage at specified spec • TPS at specified spec • Vehicle speed at specified spec • STFT at a given minimum level
EGR Monitor • PCM monitors by change in Short Term Fuel Trim • During operation of the EGR system the PCM will momentarily shut down the EGR solenoid • As a result EGR flow stops and a lean condition occurs • HO2S voltage will drop • STFT sees HO2S voltage drop and increases IPW • The PCM monitors STFT and EGR monitor is complete & Ready
Diagnostics With Mode 6 & 7 • Emission Test Failure or Readiness Monitor • Readiness Status • First checking for pending codes • Next review Datastream for errors • Perform Bi-directional test where applicable • Make repairs • Perform drive cycle to verify
Diagnostics With Mode 6 & 7 • MIL on • Check Diagnostic Trouble Code • Next review Datastream for errors • Perform Bi-directional test where applicable • Make repairs • Perform drive cycle to verify • Verify Readiness Status
Spec 10 to 30 High IAC counts LTFT over +10 MAP normal .8 to 1.5 Idle Check ignition Dirty intake valves, Injectors, or Throttle plates Leaking EGR Check fuel pressure and volume Spec 10 to 30 IAC Counts High over 40 LTFT over +10 MAP sensor high or MAF sensor low <5 Sticking IAC Dirty intake valves, Injector, or Throttle plates Check fuel pressure and volume Low Manifold pressure or compression problems IAC motor stuck open IAC Counts High
TPS Low Voltage Code • 1) KOEO • 2) Closed Throttle • Wiggle throttle shaft • If voltage varies a few tenths of a volt • Throttle body is worn • If not verify 5 volt reference and ground
MAP High Voltage Code • 1) KOER • 2) Measure Engine Vacuum at idle • Vacuum should be at spec approximate 18 in hg • If low verify • Cam to crank timing • Vacuum leak • Enriched fuel condition cause
Catalyst Efficiency MonitorPre-HO2S Post-HO2SUpstream HO2S Downstream HO2SS1 S2 800 mv 450 mv 200 mv 470 mv 450 mv 430 mv
GM CODES • Malfunction Indicator Light Codes • Hard codes • History Codes • Failure Since Clear • Failure records • Pending codes • Freeze frame
Chrysler • Switch Tests • OBD2 • Enable/Disable Tests • Idle Air Control Tests • Actuator Test Mode • Drive Cycle
FORD Tests • Output State Tests • Cylinder Balance Test • Ford OBD2 • Output Controls • Hi speed Fan On • Low Speed Fan On • All Outputs On • Drive Cycle
GM OBD2 Bi-Directional Controls • Crankshaft Relearn • EVAP/EGR Controls • Canister Purge Solenoid • Canister Vent Solenoid • EGR Control • EVAP Service • Fuel System Controls • Fuel Pump Relay • Injector Disable • Fuel Closed Loop • Fuel Trim Reset
GM OBD2 Bi-Directional Controls • Engine Indicator Lamps • Transmission Controls • Transmission Lamps • Accessory Controls • Readiness Status • O2 Tests • Drive cycles
SCAN • Is the scan tool giving good information? • Does the sensor data match what the voltmeter or lab scope displays? • Will the bi-directional confirm a problem? • Does the command that the computer uses make sense? • Always check grounds with a DVOM because of sensor data allocation data. • Always check Voltage reference supply to sensors. • Do sensors move in reaction to others?
GENERAL MOTORS • A/C REFRIGERENT • STEP 1 • COLD START ECT LESS THAN 5O DEGREES C, WITH A/C AND REAR DEFROST ON, IDLE 2.5 MINUTES IN DRIVE. BEFORE PROCEEDING TURN ACCESSORIES OFF • STEP 2 • ACCELERATE TO 55 MPH, 1/2 THROTTLE, A/C OFF • STEP 3 • 3 MININUTE STEADY STATE CRUISE 55 AND 60 MPH • STEP 4 • DECELERATE TO 20 MPH (CLUTCH OUT) NO BRAKE • STEP 5 • ACCELERATE AT 3/4 THROTTLE 55 TO 60 MPH, THEN STEADY STATE CRUISE FOR 5 MINUTES • STEP 6 • DECELERATE NO BRAKE, END OF CYCLE
GENERAL MOTORS • AIR SYSTEM • STEP 1 • COLD START LESS THAN 50 DEGREES C, WITH A/C AND REAR DEFROST ON, IDLE 2.5 MINUTES IN DRIVE. BEFORE PROCEEDING TURN ACCESSORIES OFF • STEP 2 • 3 MINUTE STEADY STATE CRUISE 55 AND 60 MPH
GENERAL MOTORS • CATALYST MONITOR • STEP 1 • VERIFY ALL OTHER IM FLAGS SET FIRST • STEP 2 • ACCELERATE AT 3/4 THROTTLE TO 55 TO 60 MPH, THEN STEADY CRUISE FOR 5 MINUTES
GENERAL MOTORS • COMPREHENSIVE COMPONENTS • STEP 1 • COLD START ECT LESS THAN 50 DEGREES C, WITH A/C AND REAR DEFROST ON, IDLE FOR 2.5 MINUTES IN DRIVE. BEFORE PROCEEDING TURN ACCESSORIES OFF • STEP 2 • ACCELERATE TO 55 MPH, 1/2 THROTTLE, A/C OFF • STEP 3 • 3 MINUTES, STEADY STATE CRUISE 55 AND 60 MPH • STEP 4 • DECELERATE TO 20 MPH (CLUTCH OUT) NO BRAKE • STEP 5 • ACCELERATE AT 3/4 THROTTLE TO 55 TO 60 MPH, THEN STEADY STATE CRUISE FOR 5 MINUTES • STEP 6 • DECELERATE NO BRAKE, END OF CYCLE
GENERAL MOTORS • EGR SYSTEM • STEP 1 • 3 MINUTE, STEADY STATE CRUISE 55 AND 60 MPH • DECELERATE (CLUTCH OUT) NO BRAKE TO LESS THAN 20 MPH
GENERAL MOTORS • EVAP SYSTEM • STEP 1 • VERIFY BOTH O2 AND CATALYST MONITORS HAVE COMPLETED • STEP 2 • IAT WITHIN 7 DEGREES OF ECT • STEP 3 • COLD START ECT LESS THAN 50 DEGREES C, WITH A/C AND REAR DEFROST ON. IDLE 2.5 MINUTES IN DRIVE. BEFORE PROCEEDING TURN ACCESSORIES OFF • STEP 4 • ACCELERATE TO 55 MPH, 1/2 THROTTLE, A/C OFF • STEP 5 • 3 MINUTE, STEADY STATE CRUISE 55 AND 60 MPH • STEP 6 • DECELERATE TO 20 MPH (CLUTCH OUT) NO BRAKE • STEP 7 • ACCELERATE AT 3/4 THROTTLE TO 55 TO 60 MPH, THEN STEADY STATE CRUISE FOR 5 MINUTES • STEP 8 • DECELERATE NO BRAKE, END OF CYCLE
GENERAL MOTORS • FUEL SYSTEM • STEP 1 • ACCELERATE TO 55 TO 60 MPH, 1/2 TO 3/4 THROTTLE, A/C OFF • STEP 2 • ACCELERATE AT 3/4 THROTTLE TO 55 TO 60 MPH, THEN STEADY STATE CRUISE FOR 5 MINUTES
GENERAL MOTORS • FULL DRIVE CYCLE • STEP 1 • COLD START ECT LESS THAN 50 DEGREES C, WITH A/C AND REAR DEFROST ON, IDLE 2.5 MINUTES IN DRIVE. BEFORE PROCEEDING TURN ACCESSORIES OFF • STEP 2 • ACCELERATE TO 55 MPH, 1/2 THROTTLE, A/C OFF • STEP 3 • 3 MINUTE, STEADY STATE CRUISE 55 AND 60 MPH • STEP 4 • DECELERATE TO 20 MPH (CLUTCH OUT) NO BRAKE • STEP 5 • ACCELERATE AT 3/4 THROTTLE TO 55 TO 60 MPH, THEN STEADY CRUISE FOR 5 MINUTES • STEP 6 • DECELERATE NO BRAKE, END OF CYCLE
GENERAL MOTORS • MISFIRE MONITOR • STEP 1 • ACCELERATE AT 3/4 THROTTLE TO 55 TO 60 MPH, THEN STEADY STATE CRUISE FOR 5 MINUTES
GENERAL MOTORS • O2 SENSOR • STEP 1 • COLD START ECT LESS THAN 50 DEGREES C, WITH A/C AND REAR DEFROST ON, IDLE 2.5 MINUTES IN DRIVE. BEFORE PROCEEDING TURN ACCESSORIES OFF • STEP 2 • 3 MINUTE, STEADY STATE CRUISE 55 AND 60 MPH
GENERAL MOTORS • O2 SENSOR HEATER • STEP 1 • COLD START ECT LESS THAN 50 DEGREES C, WITH A/C AND REAR DEFROST ON, IDLE 2.5 MINUTES IN DRIVE. BEFORE PROCEEDING TURN ACCESSORIES OFF • STEP 2 • 3 MINUTES, STEADY STATE CRUISE 55 AND 60 MPH
CHRYSLER CARS • AIR SYSTEM • STEP 1 • ENGINE WARM-UP REQUIRED, LEAVE ENGINE RUNNING 15 MINUTES • STEP 2 • ENGINE AT IDLE SPEED