P2084 – Exhaust Gas Temperature Sensor Circuit Intermittent

Title: Understanding and Troubleshooting Diagnostic Trouble Code (DTC) P2084

Introduction

Diagnostic Trouble Code (DTC) P2084 is a generic powertrain code that applies to many vehicle makes and models. It indicates an issue with the Exhaust Gas Temperature (EGT) Sensor Circuit Range/Performance on Bank 1, Sensor 2.

Urgency and Severity

While it is possible to continue driving with P2084 active in the short term, it is not advisable. This code can negatively impact engine performance, fuel economy, and emissions. It is recommended to have the issue diagnosed and repaired promptly by a qualified mechanic to prevent potential damage to the exhaust system and catalytic converter.

Technical Details

P2084 specifically refers to a range or performance problem detected in the circuit for the Exhaust Gas Temperature (EGT) Sensor on Bank 1, Sensor 2. The EGT sensor, located in the exhaust pipe downstream of the catalytic converter, monitors exhaust gas temperature to protect the converter from heat damage.

The EGT functions as a heat-sensitive resistor that converts exhaust temperature into a voltage signal sent to the Powertrain Control Module (PCM). Resistance decreases as temperature rises, resulting in higher voltage. The PCM uses this input to adjust engine timing and fuel ratio to maintain proper exhaust temperatures.

Common Causes

Potential causes of the P2084 code include:

• Faulty EGT sensor due to an internal short or failure
• Damaged, loose, or burnt EGT sensor wiring and connectors
• Exhaust leaks before the EGT sensor
• Decreased back pressure from an aftermarket exhaust system
• Issues with the PCM, such as software errors or internal faults

Diagnosis Steps

To properly diagnose the P2084 code, a mechanic will typically:

1. Scan for all stored DTCs and note freeze frame data
2. Visually inspect the EGT sensor, wiring, and connectors for damage
3. Test the EGT sensor resistance with a multimeter (normal spec is over 50 ohms)
4. Check for continuity and shorts in the EGT sensor circuit wiring
5. If no wiring faults are found, test the EGT sensor voltage signal at the PCM
6. Check for exhaust leaks and back pressure issues
7. Consider possible PCM problems if all other tests check out

Repair Solutions

Fixes for the P2084 code may involve:

• Replacing the EGT sensor if it tests faulty or is physically damaged
• Repairing damaged wiring or connectors in the EGT sensor circuit
• Fixing detected exhaust leaks that may be impacting the sensor
• Replacing a failed PCM as a last resort
• Clearing codes and retesting after repairs to verify the fix

Prevention

To help avoid P2084 and related issues:

• Regularly inspect the exhaust system for leaks and damage
• Address any EGT sensor or wiring issues promptly
• Avoid installing aftermarket exhausts that reduce back pressure
• Maintain the engine properly with regular tune-ups

Repair Cost

The cost to repair the P2084 code varies but may range from:

• DIY: $20-$300 for a new EGT sensor + $20 in misc. parts (€18-€275 + €18)
• Professional: $250-$600 (€230-€550) with parts and labor, depending on vehicle

Associated Codes

Other codes potentially related to or seen with P2084:

• P0420 – Catalyst System Efficiency Below Threshold
• P0430 – Catalyst System Efficiency Below Threshold (Bank 2)
• P2031 – Exhaust Gas Temperature Sensor Circuit Low (Bank 1, Sensor 2)
• P2032 – Exhaust Gas Temperature Sensor Circuit High (Bank 1, Sensor 2)

Frequently Asked Questions About P2084

What does the P2084 code mean?

P2084 indicates an Exhaust Gas Temperature (EGT) Sensor Circuit Range/Performance issue on Bank 1, Sensor 2. It means the powertrain control module (PCM) has detected a problem with the signal from this particular EGT sensor.

How urgent is it to address the P2084 code?

While P2084 doesn’t typically cause immediate drivability issues, it’s advisable to have it diagnosed and repaired promptly. Ignoring it could lead to potential damage to the exhaust system or catalytic converter over time.

Can I continue driving with the P2084 code active?

You can drive short distances, but it’s not recommended for extended periods. The code indicates a problem that could affect engine performance, fuel economy, and emissions if left unaddressed.

What are the common causes of the P2084 code?

Common causes include a faulty EGT sensor, damaged wiring or connectors, exhaust leaks, or in rare cases, PCM issues.

How is the P2084 code diagnosed?

Diagnosis typically involves scanning for codes, visually inspecting the EGT sensor and wiring, testing sensor resistance and circuit continuity, and checking for exhaust leaks.

What are the symptoms associated with P2084?

The primary symptom is the illuminated check engine light. There may be no other noticeable symptoms in many cases.

How much does it cost to repair the P2084 code?

Repair costs can range from $250-$600 (€230-€550) for professional service, depending on the specific issue and vehicle model. DIY repairs may cost $20-$300 for parts.

Is P2084 a manufacturer-specific code?

No, P2084 is a generic powertrain code applicable to various makes and models manufactured from 1996 onwards.

What is the function of the EGT sensor related to P2084?

The EGT sensor monitors exhaust gas temperature to protect the catalytic converter from heat damage and helps the PCM adjust engine timing and fuel ratio.

Can a faulty catalytic converter cause the P2084 code?

While a faulty catalytic converter itself doesn’t directly cause P2084, changes in exhaust system components or backpressure can affect EGT sensor readings and potentially trigger the code.

Are there any related codes that often appear with P2084?

Yes, related codes may include P0420 (Catalyst System Efficiency Below Threshold), P2031 (EGT Sensor Circuit Low), and P2032 (EGT Sensor Circuit High).

How does the EGT sensor work?

The EGT sensor is a heat-sensitive resistor that converts exhaust temperature into a voltage signal. As temperature increases, resistance decreases, resulting in higher voltage sent to the PCM.

Can aftermarket exhaust modifications cause P2084?

Yes, aftermarket exhaust systems that significantly alter backpressure or remove the catalytic converter can cause improper EGT sensor readings and trigger P2084.

What steps are involved in replacing an EGT sensor?

Replacing an EGT sensor typically involves locating the sensor in the exhaust system, disconnecting the electrical connector, unscrewing the old sensor, and installing the new one with proper torque.

Can a P2084 code clear itself?

While codes can occasionally clear themselves if the issue resolves, it’s unlikely for P2084 to clear without addressing the underlying problem.

How does P2084 differ from other EGT sensor codes?

P2084 specifically refers to Bank 1, Sensor 2. Other codes like P2080 or P2085 may refer to different banks or sensor positions.

Can extreme weather conditions trigger a P2084 code?

While extreme temperatures can affect sensor performance, P2084 is more likely caused by a genuine sensor or circuit issue rather than weather conditions.

Is it safe to clear the P2084 code without fixing the issue?

Clearing the code without addressing the underlying problem is not recommended. The code will likely return, and you risk potential damage to exhaust components.

How often do EGT sensors typically need replacement?

EGT sensors don’t have a specific replacement interval and often last the lifetime of the vehicle. However, they can fail due to extreme heat exposure or physical damage.

Can a bad oxygen sensor cause a P2084 code?

While oxygen sensors and EGT sensors are different, a malfunctioning oxygen sensor can indirectly affect exhaust temperatures. However, P2084 specifically points to an issue with the EGT sensor or its circuit.