Decoding 2000 Dodge Durango 5.9L OBD2 Test Reports: A Comprehensive Guide

Understanding your 2000 Dodge Durango 5.9L’s OBD2 test reports is crucial for maintaining its performance, ensuring emissions compliance, and identifying potential issues before they escalate into costly repairs. This guide provides an in-depth look at OBD2 testing, specifically tailored to your 2000 Dodge Durango 5.9L, helping you decipher test results and take informed action. We’ll explore the standards, potential pitfalls, and what those test reports are really telling you about your vehicle’s health.

Understanding OBD2 and Smog Check Inspections

On-Board Diagnostics, or OBD, is a computer-based system built into vehicles since the mid-1990s. OBD2 is the second generation of this system and provides comprehensive monitoring of engine and emission control components. For your 2000 Dodge Durango 5.9L, the OBD2 system is essential for both routine maintenance and mandatory smog checks in many regions.

Smog checks, also known as emissions tests, are periodic inspections to ensure vehicles meet environmental standards. A significant part of modern smog checks involves reading and interpreting data from the OBD2 system. These tests are not just about passing or failing; they offer valuable insights into your vehicle’s operational status.

The Role of OBD2 in Smog Checks

The OBD2 test during a smog check typically assesses several key areas:

Readiness Monitors: These are self-tests performed by your Durango’s computer to verify that emission control systems are functioning correctly. Monitors cover systems like the oxygen sensors, catalytic converter, evaporative system, and more.
Malfunction Indicator Lamp (MIL) or “Check Engine Light”: The MIL is designed to illuminate when the OBD2 system detects an issue that could increase emissions. Whether the MIL is on or off, and how it behaves during the test, is a critical part of the evaluation.
Communication: The smog check equipment must be able to communicate with your Durango’s OBD2 system to retrieve data. Communication failures can indicate problems with the vehicle’s computer, wiring, or the OBD2 port itself.
Permanent Diagnostic Trouble Codes (PDTCs): Introduced in later OBD2 implementations, PDTCs are codes that cannot be cleared by simply resetting the system. Their presence can signal persistent issues that need attention.

Understanding these components is the first step in effectively interpreting your 2000 Dodge Durango 5.9L’s OBD2 test reports.

Pass/Fail Standards for OBD2 Testing on Your 2000 Dodge Durango 5.9L

For a 2000 model year gasoline vehicle like your Dodge Durango 5.9L, the pass/fail standards for the OBD2 test portion of a smog check are relatively straightforward. These standards are designed to ensure vehicles meet basic emissions control functionality.

Readiness Monitor Standards for 2000 and Newer Gasoline Vehicles

Readiness monitors are crucial indicators of whether your Durango’s emission control systems have been properly evaluated. For 2000 and newer gasoline vehicles, the standard allows for only one incomplete monitor to pass the OBD test, and that exception is specifically for the Evaporative System monitor.

This means that for your 2000 Dodge Durango 5.9L:

Passing: You can pass the readiness monitor portion of the test even if the Evaporative System monitor is not complete. All other monitors ideally should be in a “ready” or “complete” state.
Failing: If you have more than one incomplete monitor (and the incomplete monitor is not the Evaporative System monitor), your vehicle will likely fail the OBD2 readiness portion of the smog check.

It’s important to note that the Misfire, Fuel, and Comprehensive Component continuous monitors are typically ignored during an OBD test on gasoline vehicles. The focus is primarily on the system-specific monitors like Catalyst, Oxygen Sensor, EGR, and Evaporative System.

Malfunction Indicator Lamp (MIL) Standards

The MIL, or “Check Engine Light,” is a direct indicator of potential emissions-related problems. The standards for the MIL are quite clear:

Pass: The MIL should illuminate briefly when the ignition is turned to the “key on, engine off” (KOEO) position. This confirms the bulb is working.
Pass: The MIL should turn off once the engine is started and running (KOER – key on, engine running), provided no active emissions faults are detected.
Fail: If the MIL does not illuminate at all during KOEO, it indicates a potential bulb failure or a problem with the MIL circuit itself, leading to a failed test.
Fail: If the MIL remains illuminated when the engine is running (KOER), it signifies that the OBD2 system has detected one or more emissions-related issues. This will result in a failed smog check.

For your 2000 Dodge Durango 5.9L, a lit “Check Engine Light” is a direct fail for the OBD2 portion of the smog check.

Communication Standards

Successful communication between the smog check equipment and your vehicle’s OBD2 system is fundamental. The standards are simple but critical:

Pass: The testing equipment must establish communication with your 2000 Dodge Durango 5.9L’s OBD2 system.
Fail: Failure to communicate can result in a failed OBD2 test. This could stem from various issues, ranging from a loose connection to more complex problems within the vehicle’s computer network.

Permanent Diagnostic Trouble Code (PDTC) Standards

While PDTC checks were officially added to smog checks in 2019, and primarily affect 2010 and newer vehicles, understanding PDTCs is still beneficial. Although your 2000 Dodge Durango 5.9L is not directly subject to PDTC failure standards in many regions, the concept is relevant to overall OBD2 system understanding.

Not Applicable (for 2000-2009 vehicles in many regions): PDTC standards are generally not applied to vehicles of your Durango’s model year in many smog check programs.
Understanding PDTCs: PDTCs are essentially diagnostic trouble codes that cannot be erased by normal means. They are designed to ensure that emission issues are properly resolved and verified before a vehicle can pass a smog check. If your Durango were a newer model subject to PDTC checks, the presence of a PDTC would lead to a failure, regardless of whether the MIL is currently illuminated.

For your 2000 Dodge Durango 5.9L, the primary focus remains on readiness monitors, MIL status, and communication during the OBD2 test.

Common OBD2 Test Issues for Vehicles Like the 2000 Dodge Durango 5.9L

While the 2000 Dodge Durango 5.9L is a robust vehicle, like all cars of this era, it can experience certain OBD2 test-related issues. Understanding these common problems can help you prepare for smog checks and troubleshoot potential failures.

Readiness Monitor Incompletion

One of the most frequent challenges with OBD2 testing, especially on older vehicles, is incomplete readiness monitors. Several factors can prevent monitors from setting to “ready” on your 2000 Dodge Durango 5.9L:

Recent Battery Disconnection or Code Clearing: If your Durango’s battery has been recently disconnected or if diagnostic trouble codes have been cleared using a scan tool, all readiness monitors will reset to “incomplete.” They require driving through specific “drive cycles” to reset.
Drive Cycle Requirements: Each monitor has a specific set of driving conditions (drive cycle) required for it to run and complete. These conditions can involve specific speeds, durations, engine temperatures, and more. If your typical driving patterns don’t match these drive cycle requirements, certain monitors might remain incomplete.
Underlying Mechanical or Sensor Issues: A genuinely malfunctioning component or sensor within an emission control system can prevent its corresponding monitor from completing. For example, a failing oxygen sensor might prevent the oxygen sensor monitor from setting to “ready.”
Vehicle Design Anomalies: In some cases, certain vehicle models are known to have inherent difficulties in completing specific monitors due to their design or software. While the 2000 Dodge Durango 5.9L isn’t specifically listed with widespread monitor issues in official documentation, age-related sensor degradation could mimic such anomalies.

Specific Monitor Concerns: For a 2000 gasoline vehicle like your Durango, the Evaporative System monitor is commonly the most challenging to complete. Other monitors like Catalyst, Oxygen Sensor, and EGR (if applicable and equipped) can also sometimes be problematic on older vehicles due to sensor aging or minor system leaks.

Communication Failures

Although less frequent than readiness monitor issues, communication failures during the OBD2 test can occur with a 2000 Dodge Durango 5.9L. Potential causes include:

OBD2 Port Damage or Corrosion: The OBD2 port itself, located typically under the dashboard, can become damaged, corroded, or have bent pins, preventing proper connection with the testing equipment.
Wiring Issues: Faulty wiring leading to the OBD2 port, or within the vehicle’s computer network (CAN bus), can disrupt communication.
Aftermarket Accessories: In rare cases, certain aftermarket accessories, particularly poorly installed stereo systems or alarms, can interfere with OBD2 communication.
Vehicle Computer Problems: While less common, issues with the Durango’s Powertrain Control Module (PCM) itself could potentially lead to communication problems.
Incorrect Test Procedure: Though uncommon with modern smog check equipment, occasionally, an incorrect test procedure or equipment malfunction could be misdiagnosed as a vehicle communication issue.

Malfunction Indicator Lamp (MIL) Issues

A lit MIL is a straightforward failure. However, issues can arise even if the light isn’t constantly on:

Intermittent MIL: An intermittent fault might cause the MIL to turn off and on. If the fault is active during the smog check, the MIL will be illuminated, leading to failure. Even if the light is off at the moment of testing, stored trouble codes can still indicate a problem.
“False” MIL Illumination (Less Likely on Durango): In some very specific and usually much newer vehicles, false MIL illumination can occur due to software glitches or sensitivity to testing equipment. This is not a typical issue for a 2000 Dodge Durango 5.9L.
MIL Bulb Failure: If the MIL bulb is burned out, it won’t illuminate during the KOEO check, causing a failure. This is a simple issue to diagnose and repair.

Interpreting Your 2000 Dodge Durango 5.9L OBD2 Test Report

After a smog check, you’ll receive an OBD2 test report. Understanding how to read this report is vital. Here’s what to look for specifically related to your 2000 Dodge Durango 5.9L:

Overall Pass/Fail Result: The report will clearly state whether your vehicle passed or failed the OBD2 portion of the test.
Readiness Monitor Status: The report will list each applicable readiness monitor and its status: “Complete” (or “Ready”) or “Incomplete” (or “Not Ready”). For your 2000 Durango, ensure all monitors are “Complete” except potentially the “Evaporative System.” Pay close attention to any other “Incomplete” monitors.
MIL Status: The report will indicate the MIL status. It should show that the MIL illuminated during KOEO and was off during KOER for a passing result. Any other behavior indicates a failure.
Diagnostic Trouble Codes (DTCs): The report will list any stored DTCs. These codes are crucial for diagnosing problems. Note down any codes present. Even if the MIL is off, stored codes can provide valuable information.
Communication Result: The report should confirm successful communication with the OBD2 system. A communication failure will be explicitly noted.
Vehicle Specific Information: The report should include your vehicle’s VIN, year, make, and model to ensure the test is correctly associated with your 2000 Dodge Durango 5.9L.

Example Scenario & Interpretation:

Let’s say your 2000 Dodge Durango 5.9L fails an OBD2 test, and the report shows:

Overall Result: Fail
MIL Status: Fail – MIL illuminated during KOER
Readiness Monitors:
- Catalyst: Complete
- Oxygen Sensor: Incomplete
- Evaporative System: Incomplete
- EGR System: Complete
- … (other monitors as applicable)
DTCs: P0131 (Oxygen Sensor Circuit Low Voltage – Bank 1 Sensor 1)
Communication: Pass

Interpretation:

The Durango failed because the MIL was on during engine running, and the Oxygen Sensor monitor is incomplete along with the Evaporative System monitor.
The DTC P0131 directly points to a problem with the Bank 1 Sensor 1 oxygen sensor circuit. This is likely the cause of the MIL and potentially the incomplete Oxygen Sensor monitor.
The incomplete Evaporative System monitor might be a separate issue or could be related to the oxygen sensor fault indirectly affecting engine operation.

Action:

Address the DTC P0131: Diagnose and repair the Bank 1 Sensor 1 oxygen sensor circuit issue. This might involve replacing the sensor, checking wiring, or addressing related problems.
After repair, clear the DTCs and drive the Durango through a proper drive cycle to reset the readiness monitors, especially the Oxygen Sensor and Evaporative System monitors.
Re-test the vehicle to confirm the MIL is off, all required monitors are “Complete,” and the DTCs are cleared.

Troubleshooting and Repair for OBD2 Failures on a 2000 Dodge Durango 5.9L

If your 2000 Dodge Durango 5.9L fails the OBD2 test, systematic troubleshooting is essential.

1. Address Communication Failures First (If Applicable):

Inspect the OBD2 Port: Check for damage, corrosion, bent pins. Clean the port if necessary.
Check Fuses: Consult your Durango’s owner’s manual for fuses related to the OBD2 port or PCM. Check and replace any blown fuses.
Professional Diagnosis: If basic checks fail, a professional mechanic can use specialized tools to diagnose wiring issues or PCM problems.

2. Deal with MIL Illumination and DTCs:

Record DTCs: Carefully note down all DTCs from the test report or use your own OBD2 scan tool to read them.
DTC Research: Use reliable resources (repair manuals, online databases) to understand the meaning and potential causes of each DTC.
Prioritize DTCs: Focus on codes related to emissions systems first.
Component Testing: Based on the DTCs, perform component-level tests (e.g., oxygen sensor testing, EVAP system leak test) to pinpoint the faulty part.
Repair and Replace: Repair wiring, vacuum leaks, or replace faulty sensors, actuators, or components as needed.
Clear DTCs: After repairs, use an OBD2 scan tool to clear all DTCs.

3. Address Incomplete Readiness Monitors:

Identify Incomplete Monitors: Note which monitors are incomplete from the test report.
Drive Cycle: Research the specific drive cycle for your 2000 Dodge Durango 5.9L to set the incomplete monitors. Drive cycles usually involve a combination of city and highway driving under specific conditions.
Patience and Proper Conditions: Drive the vehicle through the drive cycle precisely. Ensure the engine and ambient temperatures are within the required ranges. It may take multiple drive cycles for all monitors to set.
Re-test Readiness: Use an OBD2 scan tool to check readiness monitor status before re-smog checking to avoid unnecessary re-test fees. If monitors are still incomplete after several drive cycles, revisit DTC troubleshooting as an underlying issue might be preventing monitor completion.

4. Professional Help:

If you are not comfortable with automotive diagnostics and repair, or if the problems are complex, seek help from a qualified and experienced mechanic specializing in OBD2 and emissions systems.
Provide the mechanic with your OBD2 test report and all DTC information.

Maintaining OBD2 System Health in Your 2000 Dodge Durango 5.9L

Preventative maintenance and proactive care can help keep your 2000 Dodge Durango 5.9L’s OBD2 system healthy and minimize smog check issues:

Regular Engine Maintenance: Keep your engine properly tuned, perform scheduled maintenance (spark plugs, air filters, etc.), and address any engine performance issues promptly. A well-maintained engine runs cleaner and is less likely to trigger emissions faults.
Fuel System Care: Use quality fuel, maintain your fuel filter, and consider fuel system cleaners periodically to prevent fuel injector issues that can affect emissions.
EVAP System Checks: Inspect vacuum lines and hoses in the evaporative emissions system for cracks or leaks. Address any EVAP system DTCs promptly, as even small leaks can cause monitor incompletion and failures.
Oxygen Sensor Monitoring: Oxygen sensors have a limited lifespan. Consider replacing them proactively around their recommended service intervals (typically 60,000-100,000 miles) to maintain optimal fuel efficiency and emissions control.
Avoid Battery Disconnects (Unless Necessary): Minimize unnecessary battery disconnects, as they reset readiness monitors and require drive cycles for reset.
Regular OBD2 Scans: Use an OBD2 scan tool periodically to check for stored DTCs, even if the MIL is not illuminated. Addressing minor issues early can prevent them from becoming major problems and smog check failures.

By understanding OBD2 test reports, common issues, and implementing proactive maintenance, you can ensure your 2000 Dodge Durango 5.9L remains emissions compliant, performs optimally, and passes its smog checks with confidence. Remember to always consult your vehicle’s service manual and reliable repair resources for specific procedures and specifications related to your Durango model.

This image shows a typical OBD2 port location under the dashboard of a vehicle. The 2000 Dodge Durango 5.9L will have a similar port for accessing OBD2 data.

The Malfunction Indicator Lamp (MIL), often called the “Check Engine Light,” is a key indicator monitored during OBD2 tests. Its illumination signals potential emissions-related issues in your 2000 Dodge Durango 5.9L.

An example of an OBD2 scan tool interface displaying diagnostic trouble codes (DTCs) and readiness monitor status. Tools like these are essential for interpreting OBD2 test reports and troubleshooting issues in vehicles like the 2000 Dodge Durango 5.9L.