1996 LT1
OBD-II readiness applies. Use LT1-specific monitor information and the exact 1996 service conditions.
Open readiness guidance →MAKE THIS MONITOR RUN
OBD-II Readiness Assistant
Readiness is condition-based, not mileage-based. Start with the exact engine/year, then verify the monitor's prerequisites before driving farther.
CHOOSE YOUR MODEL YEAR
1997 LT1
Use the LT1 readiness section below, including the 1997 diagnostic-state information where applicable.
Open readiness guidance →1998 LS1
Use the LS1 section below. Exact monitor conditions must match 1998.
Open readiness guidance →1999 LS1
Use the LS1 section below. Exact monitor conditions must match 1999.
Open readiness guidance →2000 LS1
Use the LS1 section below. Exact monitor conditions must match 2000.
Open readiness guidance →2001 LS1
Use the LS1 section below. Do not substitute 2002 hard criteria for a 2001 car.
Open readiness guidance →2002 LS1
The 2002-specific examples on this page stay under 2002.
Open readiness guidance →CRITICAL RULE
READY does not mean the component is healthy. It means the applicable onboard diagnostic reached a determination. A diagnostic can complete and still fail.
LT1 · 1996–1997
Keep LT1 readiness separate from LS1. Clearing DTCs, interrupting PCM power, battery disconnect/discharge, or PCM programming can reset monitor status.
Before you clear anything
- Save stored/history DTCs.
- Save Freeze Frame and Failure/Fail Records where available.
- Record readiness state.
- Record the operating condition that produced the complaint.
1997 LT1 diagnostic state
Factory F-car diagnostics expose states including History, Last Test Fail, Failed Since Clear, Not Run Since Clear, Not Run This Ignition and Test Ran/Passed. Clearing codes can erase useful evidence.
1997 catalyst example
The F-car-specific LT1 catalyst monitor requires qualifying operating conditions including closed loop, sufficient ECT, and defined airflow/MAP/speed/load ranges. A NOT READY catalyst does not automatically mean a bad converter.
LS1 · 1998–2002
Exact monitor criteria vary by year. Use the year and conditions shown for your car.
Enter what you know. Unknown fields will be reported as items to verify—not guessed.
LS1 examples
1998–2000 EVAP
F-car-specific GM files establish fuel roughly 15–85%, BARO above 75 kPa, system voltage roughly 10–17 V, and qualifying cold ECT/IAT conditions. Exact cold-temperature logic varies by year.
2002 Complete System cold start
BARO >74 kPa; ECT <86°F; IAT <86°F; ECT/IAT within 14°F; 9–18 V; fuel roughly 1/4–3/4.
2002 Catalyst
BARO >74 kPa; ECT 160–248°F; IAT 5–167°F; closed loop; 6–8 minutes off idle; 11–18 V. Fan/A/C load changes can abort testing.
2002 O2
ECT >135°F; closed loop; engine running >160 seconds; 9–18 V. Manual cars may not complete at too-low RPM in overdrive.
2002 HO2S Heater
Startup ECT <122°F; startup IAT <122°F; ECT/IAT within 14°F; 11–18 V.
DO NOT DO THIS
Do not clear codes or disconnect the battery just to “reset” readiness before saving diagnostic evidence. Do not tell an owner to simply drive 50 miles when a prerequisite is not satisfied.