Hummer H2. Manual — part 43

Monitor Run Process Tip

The following is an outline of the Monitoring Run Process, including suggestions and tips in order to aid in the
process of meeting the enabling criteria for these monitors. The most efficient order has been outlined below.
For example, the first two monitors have very similar enable criteria; it is possible that the Evaporative Leak
Detection Monitor will run during the O2 Sensor Heater Monitor.

Evaporative Leak Detection Monitor (If Equipped With An LDP System)

This monitor requires a cold start, usually an overnight soak or parked for at least 8 hours without the engine
running. The engine coolant temperature must be within 10 degrees of ambient/battery temperature, and the
sensed Ambient (outside) Temperature must be between approximately 40°F and 90°F.

O2 Sensor Heater Monitor

This monitor requires a cold start, usually an overnight soak or parked for at least 8 hours without the engine
running. The engine coolant temperature must be within 10 degrees of ambient/battery temperature, and the
sensed Ambient (outside temperature) must be between approximately 0°F and 100°F. The monitor should run
directly after starting the engine.

Catalyst Monitor

The vehicle will need to be driven at a steady highway speed for a few minutes. The monitor will typically
enable and start running at approximately 35 to 40 MPH for 2.5L and 4.0L engines, 50 to 60 MPH for all
others). If the vehicle is equipped with a manual transmission, using 4th gear may assist in meeting the monitor
running criteria.

O2 Sensor Monitor

The vehicle will need to be driven for a period of time at a steady highway speed. Approximately 35 to 40 MPH
for 2.5L and 4.0L engines, 50 to 60 MPH for all others and brought to a stop for a short period of time with the
A/T left in Drive. The O2 Monitor will not run in Park or Neutral, except for vehicles equipped with a M/T.

Purge Monitor

The Purge Free cells must be updated before the monitor will run. The enabling conditions are similar to the O2
Sensor Monitor enabling conditions such as, the vehicle will need to be driven for a period of time at highway
speeds and brought to a complete stop. The Purge Flow Monitor will attempt to run every OTHER throttle
closure. If all of the parameters are met and it still does not run, with your foot firmly on the Brake, quickly
open and close the throttle, this will allow another Purge Free update, and then the Purge Flow Monitor should
run.

Misfire Monitor

Misfire monitor is continuously running during engine operation. For the Misfire monitor to be enabled, the

CARB Readiness and all additional OBD information will be cleared.

1998 Chevrolet Pickup C1500

DRIVE CYCLES OBD-II Vehicles - OBD-II Readiness Monitors

Adaptive Numerator must be learned since battery disconnect and every Key on there after (known as Power-on
learning).

The Adaptive Numerator is a software learning routine that tells the PCM where the crankshaft slots are. Since
every crankshaft is different, the PCM must learn exactly where its particular crankshaft slots are; otherwise its
RPM calculations would be wrong. After a battery disconnect and then a power-up of the PCM, the Adaptive
Numerator is set to a value which it would be at if everything were perfect (crankshaft slots, sensors, PCM
hardware, etc.). If the Adaptive Numerator is equal to the default value, no learning has happened and the
Misfire Monitor will not run.

To allow the PCM to learn the Adaptive Numerator, the following must happen:

z

Open Throttle.

z

Engine Cool Temp Above 100°F Or If Below 100°F, Wait For ECT Rise Of 59°F.

z

More than 10" Vacuum.

z

Above 1200 RPM.

z

Below 3000 RPM - A/T.

z

Below 3488 RPM - M/T.

Once the PCM has learned the Adaptive Numerator, the Misfire Monitor will run.

Fuel System Monitor

Fuel System monitor is continuously running during engine operation.

1995-2002 SBEC

OBD-II Monitor Enabling Criteria FWD/AWD SBEC PCM Equipped Vehicles

The following procedure has been established to assist technicians in the field with enabling and running OBD-
II Monitors on FWD cars and FWD/AWD vans equipped with Single Board Engine Controller (SBEC). 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.

Monitor Run Process Tip

The following is an outline of the Monitoring Run Process, including suggestions and tips in order to aid in the
process of meeting the enabling criteria for these monitors. The most efficient order has been outlined below,

NOTE:

Once the monitor run process has begun, DO NOT turn off the ignition. By
turning the ignition key off, the monitor enabling conditions will be lost. Only
the O2 Heater Monitor runs after key off.

NOTE:

By performing a battery disconnect, or erasing diagnostic trouble codes, the
CARB Readiness and all additional OBD information will be cleared.

1998 Chevrolet Pickup C1500

DRIVE CYCLES OBD-II Vehicles - OBD-II Readiness Monitors

the first two monitors have very similar enable criteria, so it is possible that the Evaporative Leak Detection
Monitor will run while operating the vehicle to enable the Catalyst Monitor.

Evaporative Leak Detection Monitor (If Equipped)

This monitor requires a cold start, usually an overnight soak or parked for at least 8 hours without the engine
running. The engine coolant temperature must be within 10 degrees of ambient/battery temperature, and the
sensed Ambient (outside) temperature must be between approximately 40°F and 90°F.

Catalyst Monitor

The vehicle will need to be driven at a steady highway speed for a few minutes. The monitor will typically
enable and start running around 45 to 60 mph under normal driving conditions. If the vehicle is equipped with a
manual transmission, using 4th gear may assist in meeting the monitor running criteria.

EGR Monitor

The EGR monitor enable conditions are basically that the vehicle is in closed loop operation and coolant
temperature above 170°F. It is necessary to maintain the TPS, MAP, MPH and RPM ranges at a constant with
very little fluctuation to allow the monitor to complete during the cycle.

O2 Sensor Monitor

The vehicle will need to be driven for a period of time at highway speeds and brought to a complete stop for a
short period of time, with the A/T left in Drive the monitor should run. The O2 Monitor will not run in Park or
Neutral on A/T equipped vehicles.

Purge Monitor

The Purge Free cells must be updated before the monitor will run. The enabling conditions are similar to the O2
Sensor Monitor enabling conditions such as, the vehicle will need to be driven for a period of time at highway
speeds and brought to a complete stop. The Purge Flow Monitor will attempt to run every OTHER throttle
closure. If all of the parameters are met and it still does not run, with your foot firmly on the Brake, quickly
open and close the throttle, this will allow another Purge Free update, and then the Purge Flow Monitor should
run.

O2 Sensor Heater Monitor

The vehicle will need to be driven for a period of time at highway speeds to satisfy the enabling conditions for
the O2 Sensor Heater Monitor. The monitor runs with the ignition key off after vehicle operation. Allow the
vehicle to hot soak for a few minutes before checking to determine if the monitor completed the cycle. Turning
the key on prematurely will abort the monitor test and the vehicle will have to be driven to arm the enabling
conditions again.

Misfire Monitor

Misfire monitor is continuously running during engine operation. For the Misfire monitor to be enabled, the
Adaptive Numerator must be learned since battery disconnect and every Key on there after (known as Power-on

1998 Chevrolet Pickup C1500

DRIVE CYCLES OBD-II Vehicles - OBD-II Readiness Monitors

learning).

The Adaptive Numerator is a software learning routine that tells the PCM where the crankshaft slots are. Since
every crankshaft is different, the PCM must learn exactly where its particular crankshaft slots are; otherwise its
RPM calculations would be wrong. After a battery disconnect and then a power-up of the PCM, the Adaptive
Numerator is set to a value which it would be at if everything were perfect (crankshaft slots, sensors, PCM
hardware, etc.). If the Adaptive Numerator is equal to the default value, no learning has happened and the
Misfire Monitor will not run.

To allow the PCM to learn the Adaptive Numerator, the following must happen:

z

Open Throttle.

z

Engine Cool Temp Above 100°F, Or If Below 100°F Wait for ECT Rise of 59°F.

z

More Than 10" Vacuum.

z

Above 1200 RPM.

z

Below 3000 RPM - A/T.

z

Below 3488 RPM - M/T.

Once the PCM has learned the Adaptive Numerator, the Misfire Monitor will run.

Fuel System Monitor

Fuel System monitor is continuously running during engine operation.

FORD MOTOR CO.

1996-99 GASOLINE MODELS

Introduction

The purpose of the OBD-II drive cycle is to execute the OBD-II monitors and identify any concerns with the
OBD-II system. The DTC P1000 code will be erased of all OBD-II monitors have completed during the OBD-II
drive cycle.

The scan tool will be used to observe the status of each OBD-II monitor at the completion of the OBD-II drive
cycle. The completion status of the Exhaust Gas Recirculation (EGR), Heated Oxygen Sensor (HO2S),
Evaporative emission (EVAP), secondary Air Injection (AIR) (if applicable) and catalyst efficiency monitors
can be monitored during the OBD-II drive cycle by viewing the On-Board Readiness Menu on the scan tool.

Vehicle Preparation for OBD-II or Monitor Repair Verification Drive Cycle

WARNING:

Strict observance of posted speed limits and attention to driving
conditions are mandatory when proceeding through the following drive
cycles.

1998 Chevrolet Pickup C1500

DRIVE CYCLES OBD-II Vehicles - OBD-II Readiness Monitors