P0408 RAM Code - Exhaust Gas Recirculation Sensor 'B' Circuit High
Quick Answer
Early Exhaust Gas Recirculation (EGR) systems components include an EGR Valve, an Engine Control Module (ECΜ) Controlled Vacuum Switch Valve or EGR Solenoid, and an EGR Vacuum Modulator. Common causes include Faulty EGR volume control solenoid valve, Carbon built up on EGR valve, EGR volume control solenoid valve harness is open or shorted. Severity is Moderate - service should be scheduled soon. The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.
- What it means
- P0408 RAM indicates Exhaust Gas Recirculation Sensor 'B' Circuit High.
- Common causes
- Common causes include Faulty EGR volume control solenoid valve, Carbon built up on EGR valve, EGR volume control solenoid valve harness is open or shorted.
- Severity
- Moderate - service should be scheduled soon.
- Can I drive?
- The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.
Code P0408 RAM Description
The EGR system on recently built vehicles uses a step motor to control the flow rate of EGR from the exhaust manifold. This motor has four winding phases. It operates according to the output pulse signal of the ECΜ. Two windings are turned ON and OFF in sequence. Each time an ON pulse is issued, the valve opens or closes, changing the flow rate. When no change in the flow rate is needed, the ECΜ does not issue the pulse signal. Α certain voltage signal is issued so that the valve remains at that particular opening.
What are the Possible Causes of the DTC P0408 RAM?
- Faulty EGR volume control solenoid valve
- Carbon built up on EGR valve
- EGR volume control solenoid valve harness is open or shorted
- EGR volume control solenoid valve circuit poor electrical connection
- Faulty EGR temperature sensor and circuit
How to Fix the DTC P0408 RAM?
Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P0408 RAM code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.
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Frequently Asked Questions about P0408 RAM Code
1. What are the common symptoms of OBDII code P0408?
The common symptoms of code P0408 include rough idling, decreased fuel efficiency, engine stalling, and the illumination of the Check Engine Light.
2. What does the OBDII code P0408 indicate?
OBDII code P0408 indicates a problem with the Exhaust Gas Recirculation (EGR) Sensor 'B' Circuit High. This means that the voltage signal from the EGR sensor is higher than the expected range.
3. What are the possible causes of OBDII code P0408?
Possible causes of code P0408 include a faulty EGR sensor, damaged wiring or connectors in the EGR circuit, a malfunctioning EGR valve, or issues with the vehicle's Engine Control Module (ECM).
4. How can I diagnose the cause of OBDII code P0408?
Diagnosing code P0408 usually involves using a scan tool to retrieve the code, checking the EGR sensor's voltage output, inspecting the EGR valve and related components for damage, and testing the wiring and connectors for continuity.
5. Can I still drive my vehicle with OBDII code P0408?
It is not recommended to drive your vehicle with OBDII code P0408 unresolved, as it can lead to further damage to the engine and emissions system. It is best to address the issue promptly.
6. How can I repair OBDII code P0408?
Repairing code P0408 may involve replacing the EGR sensor, repairing or replacing damaged wiring or connectors, cleaning or replacing the EGR valve, or addressing any underlying issues with the ECM.
7. Can a DIY enthusiast fix OBDII code P0408?
Depending on your skill level and access to tools, a DIY enthusiast may be able to address OBDII code P0408 by following diagnostic procedures, replacing components, and clearing the code with a scan tool.
8. Will resetting the Check Engine Light resolve OBDII code P0408?
Simply resetting the Check Engine Light without addressing the underlying issue causing code P0408 will not resolve the problem. It is important to diagnose and repair the root cause of the code.
9. How long does it typically take to repair OBDII code P0408?
The time it takes to repair code P0408 can vary depending on the exact cause of the issue, the availability of parts, and the skill level of the person performing the repairs. It may range from a few hours to a day.
10. What happens if OBDII code P0408 is ignored?
Ignoring OBDII code P0408 can lead to poor engine performance, decreased fuel efficiency, increased emissions, and potential damage to other engine components over time. It is advisable to address the issue promptly.
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