P0490 OBD-II Trouble Code: Exhaust Gas Recirculation "A" Control Circuit High

Our certified mechanics come to you · 12-month, 12,000-mile warranty

SCHEDULE P0490 DIAGNOSTIC Get a fair and transparent estimate upfront
Red-stars EXCELLENT RATING ON

Cost of diagnosing the P0490 code

P0490 is a diagnostic trouble code (DTC) for "Exhaust Gas Recirculation "A" Control Circuit High". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic for $70.00. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $30.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.

Cars Estimate Credit towards follow-up repair Earliest Availability
Ford$70.00$30.00
Toyota$70.00$30.00
BMW$70.00$30.00
SCHEDULE P0490 DIAGNOSTIC Get a fair and transparent estimate upfront

check engine light

P0490 code definition

If the powertrain control module, or PCM, has detected an abnormally high rate of

voltage flow within the exhaust gas recirculation system, or EGR, it will store the P0490

code. It is commonly associated with the P0489 code, which indicates that the voltage

within the same system is abnormally low.

What the P0490 code means

The EGR works to prevent NOx from forming in the cylinders of a vehicle. This is

achieved by a computer system that opens and closes the EGR in order to maintain

cylinder head temperature. If this computer fails to register a voltage change in the

EGR, it will believe that the EGR is not opening or closing, and will cause the P0490

code to be stored in the PCM.

What causes the P0490 code?

Most commonly, a clogged EGR or DPFE passage are to blame for the P0490 code.

There may also be a short to the battery voltage, or a failed ECU causing this code.

Other causes may include:

  • Faulty EGR sensor

  • Faulty EGR valve

  • Faulty EGR solenoid

  • Faulty MAP sensor

  • Broken vacuum line

  • Faulty connectors or electrical wiring

What are the symptoms of the P0490 code?

In most cases, the P0490 code is not preceded by any symptoms. The vehicle owner

will be alerted to a problem by the illumination of the Check Engine Light. However,

some vehicles may run roughly, or may be difficult to start. Vehicle owners may

experience a decrease in power, or a decrease in fuel economy.

How does a mechanic diagnose the P0490 code?

In order to diagnose the P0490 code, a technician needs to check the PCM memory

with an OBD-II scanner. When the P0490 code is returned, they should inspect the

electrical wiring and connectors, to be sure that the issue isn’t being caused by a simple

short or disconnected wire. When any issues in the wiring have been addressed, they

should clear the code and retest the system. If the code is still being stored, they will

then consider other repair options to address the P0490 code.

Common mistakes when diagnosing the P0490 code

The most common mistake when diagnosing the cause of the P0490 code is to

automatically replace the EGR valve. This part is not faulty as often as many other

components of the EGR system.

How serious is the P0490 code?

Because the buildup of NOx in a vehicle’s cylinders can be very harmful, the presence

of the P0490 code is very serious. A properly operating EGR is also a key component

for getting good fuel economy. This repair should be addressed immediately.

What repairs can fix the P0490 code?

After ensuring that the electrical components are not responsible for the storage of the

P0490 code, the mechanic has several repair options available:

  • Use a scanner to monitor EGR function, and manually compare the information to the

manufacturer’s specifications.

necessary.

the operation.

  • Remove the EGR valve and clear any clogs.

  • Check that the computer is working correctly, and replace if necessary.

  • Test all connectors and wiring for the PCM, and repair or replace as necessary.

After each of these repairs, the code should be cleared and the system should be

retested. The more repairs that are checked off the list, the easier it will be for a

technician to narrow down the true cause behind the P0490 code.

Additional comments for consideration regarding the P0490 code

If the P0490 code is detected in a vehicle that has fewer than 100,000 miles, check the

manufacturer’s warranty or dealership’s warranty. The EGR system is typically covered

under standard warranties, and the cost of replacement or repair may be covered by the

warranty.

Need help with a P0490 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to

diagnose and repair your vehicle. Get a quote and book an appointment

online or speak to a service advisor at 1-800- 701-6230.

P0490
trouble codes
Check Engine Light

Fast and easy Check Engine Light is on Inspection service at your home or office.

SCHEDULE P0490 DIAGNOSTIC
Get a fair and transparent estimate upfront

Recent Check Engine Light is on Inspection reviews

Excellent Rating


YourMechanic Check Engine Light is on Inspection Service

Average Rating

4.5/5

Number of Reviews

3,901

Rating Summary
3,566
166
43
25
101
3,566
166
43
25
101

Gregory

28 years of experience
141 reviews
Gregory
28 years of experience
Greg was on time, very personable and got right to work. Would use him again. appreciated the fact he took the time to familiarize himself with the engine light codes for my 1993 Ford before he came to the appointment.
1993 FORD E-350 ECONOLINE CLUB WAGON - CHECK ENGINE LIGHT IS ON - DENVER, COLORADO

Joseph

30 years of experience
432 reviews
Joseph
30 years of experience
Absolutely great! Knowledgeable & trustworthy! Will def be requesting him again on my next issue
2005 FORD ESCAPE - CHECK ENGINE LIGHT IS ON - DALLAS, TEXAS

Emmette

33 years of experience
269 reviews
Emmette
33 years of experience
Answered all my questions . Very Pleasant to talked to . Completely satisfied .
2006 NISSAN 350Z - CHECK ENGINE LIGHT IS ON - WOODBRIDGE, VIRGINIA

Ben

38 years of experience
883 reviews
Ben
38 years of experience
I was very pleased with Ben he was very efficient and knowledgeable.
2004 BMW 330XI - CHECK ENGINE LIGHT IS ON - HOUSTON, TEXAS

More related articles

How to Buy Fuel Treatments
Adding a fuel additive to your gas tank when you fill up is one way to clean vital engine parts of deposits, improve the performance of your engine,...
The Traveler’s Guide to Driving in Malaysia
CraigBurrows / Shutterstock.com Malaysia is a popular destination for many tourists today. The country has amazing sights and attractions that you will want to explore....
Veteran and Military Driver Laws and Benefits in Idaho
The state of Idaho offers a number of benefits and perks for those Americans who have either served in an Armed Forces branch in the...

Related questions

Q: Throttle body position sensor

The rumbling noise may be coming from the loose catalyst in the exhaust piping. It would need to be verified by a road test to listen to the noise. If the catalyst is breaking up in the exhaust then the...

Q: How do i reset the computer after i change the crank shaft position censor?

To reset the check engine light you can disconnect the battery via the negative battery terminal and let the vehicle sit for an hour before reconnecting the battery. This will drain all of the power from the electronics and clear...

Q: My car has poor acceleration.

From what you've described, it sounds like you may have a mass airflow sensor that is giving incorrect data for the altitude you are at. This can cause low power, pinging, and O2 codes indicating a too lean condition. A...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1-800-701-6230 · hi@yourmechanic.com