In-Use Monitor Performance Ratio
Manufacturers are required to implement software algorithms that track in-use performance for each of the following components: catalyst bank 1, catalyst bank 2, primary oxygen sensor bank 1, primary oxygen sensor bank 2, evaporative 0.020" leak detection system, EGR system, and secondary air system, and secondary oxygen sensor bank 1 and secondary oxygen sensor bank 2 for 2010 MY and beyond. The numerator for each component or system tracks the number of times that all conditions necessary for a specific monitor to detect a malfunction have been encountered. The denominator for each component or system tracks the number of times that the vehicle has been operated in the specified conditions.
If a vehicle utilizes Variable Valve Timing (VVT) in place of EGR, the VVT in-use data is reported in place of the EGR in-use data. If a vehicle utilizes both an EGR system and a VVT system, the PCM tracks the in-use performance data for both monitors, but reports only the data for the system with the lowest numerical ratio.
If a vehicle utilizes an evaporative system monitor that is certified to 0.040" or 0.150" requirements instead of 0.020" requirements, the PCM reports the 0.040" monitor or 0.150" monitor in-use performance data in place of the 0.020" in-use performance data.
The table below shows which monitors must complete to increment each IUMPR numerator.
that EVAP monitor takes longer to find a fault than to pass, therefore, it must use a "ghost monitor" that tracks whether the monitor could have found a fault, had a fault been present. To increment the IUMPR counter for EVAP, the 0.020" leak check must maintain monitoring conditions for 45 minutes after shutdown. The 0.040" leak check must maintain monitoring condition based on the longest time it take to pull to target vacuum. If the actual monitor fails, the ghost monitor does not run and the numerator is incremented.
that Catalyst monitor uses EWMA. The numerator increments after the catalyst monitor completes. After a code clear, the numerator increments after catalyst monitor completes 6 times.
Ignition Cycle Counter
- "Engine start" is defined as the point when the engine reaches a speed 150 rpm below the normal, warmed-up idle speed (as determined in the drive position for vehicles equipped with an automatic transmission).
Ignition cycle counter will increment after engine start >= 1 s for non-hybrid vehicle
- "Propulsion system active" is the state where the powertrain (e.g., engine, electric machine) is enabled by the driver (e.g., after ignition on for conventional vehicles, after power button pushed for some hybrid vehicles, after remote start activation) such that the vehicle is ready to be used (e.g., vehicle is ready to be driven, ready to be shifted from "park" to "drive", heating, ventilation, and air conditioning (HVAC) turned on to condition cabin prior to driving), when such an HVAC operating mode could eventually cause a fueled start of the engine). For purposes of this definition, "the state where the powertrain is enabled" does not include activations that are not driver-initiated (e.g., conditions where portions of the vehicle system wake up to perform OBD II monitoring or off-board charging).
Ignition cycle counter will increment after propulsion system active for >= 1 s for hybrid vehicle
General Denominator Counter
- Ambient Temperature >= -7 deg C (20 deg F)
- Barometric pressure >= 752 hPA (8, 000 ft altitude)
- Time since engine start (or propulsion system active for hybrid) => 600 s
- Time with vehicle speed greater or equal to than 40 kph (25 mph) >= 300 s
- Continuous vehicle operation at idle time (i.e., accelerator pedal released with vehicle speed <= 1.6 kph (1 mph)) >= 30 s
- For hybrid vehicles, cumulative fueled engine operation >= 10 s
General Denominator counter will increment if all the following conditions are met:
Special requirements for Denominator for VVT Monitor
VVT Monitor requires all the conditions for the general denominator to increment and VVT system commanded on for a continuous time >= 10 s
Conditions for interrupting Numerators are described in the individual monitor descriptions.
Conditions for interrupting monitor specific Denominators are as, follows:
- Oxygen sensors
- MAP/MAF sensors
- Air temperature sensors
- Canister purge solenoid
- Fuel rail pressure sensor
- Fuel volume regulator
- Crank position sensor
- Fuel injectors
- Ignition coils
- Knock sensors
- Engine coolant temperature sensors
- Fuel monitor control errors
- Torque control errors
- VVT errors
Catalyst Monitor - In addition to faults that disable the general denominator faults on any of the following sensors or actuators:
- MAP/MAF sensors
- Air temperature sensors
- Canister purge solenoid
- Fuel rail pressure sensor
- Fuel volume regulator
- Crank position sensor
- Cam position sensors
- Fuel injectors
- Ignition coils
- Knock sensors
- Engine coolant temperature sensors
- Lambda control errors
- Torque control errors
- Throttle position sensor
- VVT errors
- Vehicle speed errors
Oxygen Sensor Monitor - In addition to faults that disable the general denominator faults on any of the following sensors or actuators:
- Crank position sensor
- Cam position sensors
- VVT Solenoids
- ECT Sensor
- Throttle position sensor
- MAP/MAF sensor
VVT Monitor - In addition to faults that disable the general denominator faults on any of the following sensors or actuators
- Throttle position sensors
- Crank position sensor
- Vehicle speed sensor
- MAP/MAF sensor
- Intake air temperature sensor
- Engine coolant temperature sensor
Conditions for interrupting General Denominators are as follows; faults on any of the following sensors and actuators:
| IUMPR Counter Numerator | Controlling Monitor |
| Catalyst Monitoring Bank 1 | P0420 |
| Catalyst Monitoring Bank 12 | P0430 |
| O2 Sensor Monitoring Bank 1 | P0133 |
| O2 Sensor Monitoring Bank 2 | P0153 |
| EGR and/or VVT System Monitoring | |
| EGR (if supported) | P0400/P0401 |
| VVT (if supported) | P0011/P0012/P0014/P0015 P0021/P0022/P0024/P0025 |
| EVAP Monitoring | |
| 0.020" monitoring (California) | P0456 |
| 0.040" monitoring (Federal) | P0442 |
| 0.150" monitoring (HD OBD) | P0455 |
| AIR Monitoring | P0410/P0491/P2448 |
| Secondary O2 Sensor Monitoring Bank 1 | P013A/P013E |
| Secondary O2 Sensor Monitoring Bank 2 | P013C/P014A |
The data is output using Service $09, Info Type $08. An example for the data format is show below. The monitoring ratio is the monitor numerator divided by the monitor denominator.
| Test Equipment Display | Data | Monitoring Ratio |
| OBDCOND - number of times OBD monitoring conditions encountered (General Denominator) | 15 counts | |
| IGNCNTR - number of times that the engine has been started | 27 counts | |
| CATCOMP1 - times that all conditions necessary to detect a catalyst system bank 1 malfunction have been encountered (numerator) | 14 counts | 0.93 |
| CATCOND1 - times that the vehicle has been operated in the specified catalyst monitoring conditions (denominator) | 15 counts | 0.93 |
| CATCOMP2 - times that all conditions necessary to detect a catalyst system bank 2 malfunction have been encountered (numerator) | 0 counts | N/A |
| CATCOND2 - times that the vehicle has been operated in the specified catalyst monitoring conditions (denominator) | 0 counts | N/A |
| O2SCOMP1 - times that all conditions necessary to detect an oxygen sensor bank 1 malfunction have been encountered (numerator) | 19 counts | 1.27 |
| O2SCOND1 - times that the vehicle has been operated in the specified oxygen sensor monitoring conditions (denominator) | 15 counts | 1.27 |
| O2SCOMP2 - times that all conditions necessary to detect an oxygen sensor bank 2 malfunction have been encountered (numerator) | 0 counts | N/A |
| O2SCOND2 - times that the vehicle has been operated in the specified oxygen sensor monitoring conditions (denominator) | 0 counts | N/A |
| EGRCOND - times that all conditions necessary to detect an EGR/VVT system malfunction have been encountered (numerator) | 19 counts | 1.27 |
| EGRCOMP - times that the vehicle has been operated in the specified EGR/VVT system monitoring conditions (denominator) | 15 counts | 1.27 |
| AIRCOND - times that all conditions necessary to detect an AIR system malfunction have been encountered (numerator). | 0 counts | N/A |
| AIRCOMP - number of times that the vehicle has been operated in the specified AIR system monitoring conditions (denominator). | 0 counts | N/A |
| EVAPCOMP - of times that all conditions necessary to detect a 0.020" (or 0.040") EVAP system leak malfunction have been encountered (numerator) | 16 counts | 1.33 |
| EVAPCOND - times that the vehicle has been operated in the specified EVAP system leak malfunction monitoring conditions (denominator) | 12 counts | 1.33 |
| SO2SCOMP1 - times that all conditions necessary to detect a secondary oxygen sensor bank 1 malfunction have been encountered (numerator) | 17 counts | 1.13 |
| SO2SCOND1 - times that the vehicle has been operated in the specified secondary oxygen sensor monitoring conditions (denominator) | 15 counts | 1.13 |
| SO2SCOMP2 - times that all conditions necessary to detect a secondary oxygen sensor bank 2 malfunction have been encountered (numerator) | 0 counts | N/A |
| SO2SCOND2 - times that the vehicle has been operated in the specified secondary oxygen sensor monitoring conditions (denominator) | 0 counts | N/A |