On-Board Diagnostics

DESCRIPTION
OPERATION

DESCRIPTION

Acronym	Description
APPS	Accelerator Pedal Position Sensor
AAT	Ambient Air Temperature
ABS	Anti-Lock Brake System
ASBS	Auto Sway Bar System
ASCM	Air Suspension Control Module
ASD	Auto Shut Down
BARO	Barometric
BCM	Body Control Module
CGW	Central Gateway
CKP	Crankshaft Position Sensor
CMP	Camshaft Position Sensor
CMTC	Compass/Mini-Trip Computer
DCHA	Diesel Cabin Heater Assist
DLC	Data Link Connector
DTC	Diagnostic Trouble Code
EATX	Electronic Automatic Transaxle
ECT	Engine Coolant Temperature
ECM	Engine Control Module
EGR	Exhaust Gas Recirculation
ETC	Electronic Throttle Control
GEN	Generator
GPEC	Global Powertrain Engine Controller
FCM	Front Control Module
FDCM	Final Drive Control Module
IAT	Intake/Inlet Air Temperature
IAC	Idle Air Control
IOD	Ignition Off-Draw
IPM	Integrated Power Module
JTEC	Jeep Truck Engine Controller
KS	Knock Sensor
KIN	Keyless Ignition Node

LDP	Leak Detection Pump
MAP	Manifold Air Pressure
MDS	Multi Displacement System
MIC	Mechanical Instrument Cluster
MIL	Malfunction Indicator Lamp
MTV	Manifold Tuning Valve
NGC	Next Generation Controller
NVLD	Natural Vacuum Leak Detection
O2S	Oxygen Sensor
OBD	On Board Diagnostic
PDC	Power Distribution Center
PCI	Programmable Communication Interface
PCM	Powertrain Control Module
PCV	Positive Crankcase Ventilation
PEP	Peripheral Expansion Port
SBEC	Single Board Engine Controller
SCM	Steering Control Module
S/C	Speed Control
SKIM	Sentry Key Immobilizer Module
SKREEM	Sentry Key Remote Entry Module
SOL	Solenoid
SRV	Short Runner Valve
TCM	Transmission Control Module
TCC	Torque Converter Clutch
TIP	Throttle Inlet Pressure
TIPM	Totally Integrated Power Module
TP	Throttle Position
TPMS	Tire Pressure Monitor System
TRS	Transmission Range Sensor
VSS	Vehicle Speed Sensor/Signal
WIN	Wireless Ignition Node

OPERATION

The following procedure has been established to assist technicians in the field with enabling and running OBD II Monitors. The order listed in the following procedure is intended to allow the technician to effectively complete each monitor and to set the CARB Readiness Status in the least time possible.

NOTE:
Once the monitor run process has begun, do not turn off the ignition. By turning the ignition key off, monitor enabling conditions will be lost. EVAP Monitor runs after key off. By performing a Battery Disconnect, or Selecting Erase DTCs, the CARB Readiness and all additional OBD II information will be cleared.

Monitor Preliminary Checks:

Plug a scan tool into the vehicle's Data Link Connector (DLC).

Turn the ignition, KEY ON - ENGINE OFF. Watch for the MIL lamp illumination during the bulb check. MIL lamp must illuminate, if not, repair MIL lamp.

Using a scan tool check for Powertrain related DTCs.

Verify that No Emissions Related DTCs are Present. If an Emissions DTC is Present, the OBD II Monitors may not run and the CARB Readiness will not update.
The Emissions related DTC, will need to be repaired, then cleared. By clearing DTCs, the OBD Monitors will need to be run and completed to set the CARB Readiness Status.

Using the scan tool check the CARB Readiness Status.

Do all the CARB Readiness Status Locations read YES?

YES - all monitors have been completed and this vehicle is ready to be I/M or Emission Tested.
NO - then the following procedure needs to be followed to run/complete all available monitors.

NOTE:
Only the monitors, which are not YES in the CARB Readiness Status, need to be completed. Specific criteria need to be met for each monitor. The most efficient order to run the monitors has been outlined below, including suggestions to aid the process.

Evaporative Emission System Leak Detection with Purge Monitor

This monitor requires a cool down cycle, usually an overnight soak for at least 8 hours without the engine running. The ambient temperature must decrease overnight - parking the vehicle outside is advised. To run this test the fuel level must be between 15-85% full. Criteria for EVAP monitor:

Engine off time greater than one hour .
Fuel Level between 15% and 85%.
Start Up ECT and IAT within 10°C (18°F).
Vehicle started and run until Purge Monitor reports a result.

NOTE:
If the vehicle does not report a result and the conditions where correct. It may take up to two weeks to fail the small leak monitor. DO NOT use this test to attempt to determine a fault. Use the appropriate service information procedure for finding a small leak. If there are no faults and the conditions are correct this test will run and report a pass. Note the Small leak test can find leaks less than 10 thousands of an inch. If a small leak is present it takes approximately one week of normal driving to report a failure.

Catalyst / O2 Monitor

The Catalyst and O2 Monitor information are acquired and processed at the same time. Most vehicles will need to be driven at highway speed (less than 50 mph) (73km/h) for a few minutes. Some vehicles run the monitor at idle in drive. If the vehicle is equipped with a manual transmission, using 4th gear may assist in meeting the monitor running criteria.

Engine RPM between 1200 to 3000.
Enginetemperature greater than 70°C (158°F)
Engine run time greater than 92 seconds
MAP between 10 - 20 kPa (7.5 - 15 Hg)
Vehicle speed between 20 - 70 mph (29–103 km/h)

EGR Monitor

After the vehicle has reached the below conditions and during a throttle decel the EGR monitor will run.

Engine RPM between 1375 - 2500
Engine temperature greater than 70°C (158°F)
Engine run time greater than 125 seconds
Vehicle speed between 25 - 70 mph (37–103 km/h)

O2 Sensor Heater Monitor

This monitor is now continuously running once the heaters are energized. Pass information will be processed at power down.

Mis-Fire Monitor

The Misfire Monitor is a continuous two-trip monitor. The monitor uses two different tests/counters:

NOTE:
The Adaptive Numerator must be learned before the PCM will run the Mis-Fire Monitor. The PCM updates the Adaptive Numerator at every key-ON, and is relearned after battery disconnect. The Misfire Monitor will not run until the Adaptive Numerator has updated since the last battery disconnect. If the Adaptive Numerator is equal to the default value then the PCM knows that the Adaptive Numerator has not been learned and does not permit the Misfire Monitor to run. If the Adaptive Numerator exceeds a calibrated percentage, the PCM sets a DTC for CKP NOT LEARNED and illuminates the MIL.

200 Revolution Counter - Looks for misfire that can cause immediate catalyst damage.
1000 Revolution Counter - Looks for misfire that can cause emissions to increase 1.5 times the Federal Test Procedure (FTP) standards. This test must also identify misfire percentages that might cause a “durability demonstration vehicle” to fail an Inspection and Maintenance Program tailpipe emissions test.