This article addresses the process of establishing OBDII readiness codes on a 1995 Volvo 850 GLT, specifically focusing on instances where the “Check Engine” light illuminates and a scan tool reveals an “Incomplete” or “Not Ready” status for one or more OBDII monitors. This information is crucial for passing emissions tests. While the original document focused on 1996-1998 models, this article clarifies the procedure for a 1995 Volvo 850 GLT, which utilizes the Motronic 4.3 system.
Understanding OBDII Readiness Codes in a 1995 Volvo 850 GLT
OBDII (On-Board Diagnostics II) is a system that monitors your vehicle’s emissions system. Readiness monitors track the performance of various components and report their status as “Ready” or “Not Ready.” A “Not Ready” status indicates a specific monitor hasn’t completed its diagnostic cycle. For a 1995 Volvo 850 GLT to pass an emissions inspection, all OBDII monitors must be in a “Ready” state. Common causes for “Incomplete” OBDII codes include:
- Recently cleared Diagnostic Trouble Codes (DTCs)
- Disconnected battery
- Insufficient driving since the last code clearing or battery disconnection
Example of a Volvo 850 engine bay. Note: The actual configuration may vary depending on the specific model and year.
Establishing OBDII Readiness on a 1995 Volvo 850 GLT
Setting the readiness codes on a 1995 Volvo 850 GLT with Motronic 4.3 requires specific driving conditions. Generic OBDII scan tools may show all readiness codes changing from “Complete” to “Incomplete” when the ignition is cycled on these models. It’s crucial not to turn off the engine during the emissions test until the OBDII check is complete. Volvo recommends using their specialized scan tool, the Volvo Systems Tester (VST), for accurate monitoring. However, generic scan tools can still indicate “Trip” completion. Two complete “Trips” are necessary to set readiness. A “Trip” consists of:
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Flywheel Adaptation: This process ensures accurate misfire detection. Drive in second or third gear (2500-3500 RPM) and decelerate without braking multiple times until adaptation values stop changing.
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Driving Cycle: This involves a specific sequence of driving conditions, including city driving, highway driving, and idling periods, detailed in the original Volvo documentation. Maintain steady throttle application during these cycles.
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Monitoring with a Scan Tool: Use a scan tool to monitor the status of individual readiness codes (represented by DTC/EFI codes). As each monitor completes, its corresponding code will change to “Ready” or “Complete.”
Example of a generic OBDII scan tool displaying readiness monitor status. Note: Actual display may vary.
Specific Considerations for Motronic 4.3
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Flywheel Adaptation: The VST cannot read flywheel adaptation status on Motronic 4.3 systems. Assume it’s not set and perform the adaptation procedure before each “Trip.”
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Readiness Status: The VST cannot directly read readiness status on Motronic 4.3 systems. Completion of two “Trips” indicates readiness.
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Specific Diagnostic Tests: For individual monitor issues, utilize the VST’s “Quick Test” function for Leakage Diagnosis and SAS (Secondary Air System) Diagnosis.
Addressing Individual Incomplete Monitors
If after completing two trips, specific monitors remain “Not Ready,” refer to the original Volvo document for targeted driving procedures to address individual DTC/EFI codes. This may involve specific engine speed, load, and driving duration requirements.
Conclusion
Successfully setting OBDII readiness codes on a 1995 Volvo 850 GLT requires understanding the specific driving procedures and limitations of the Motronic 4.3 system. Adhering to the outlined steps and utilizing a scan tool for monitoring ensures your Volvo is prepared for emissions testing. Consult the original Volvo documentation for detailed instructions and DTC/EFI code definitions. Remember, passing emissions tests contributes to cleaner air and a healthier environment.
