Readiness Sensor Tuning

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As some of you may or may not already know, every time you unplug the battery in your vehicle and or flash the PCM with a new tune, all your sensors that require a drive cycle to complete a readiness status will now show as incomplete until you initiate the  drive cycle (without flashing the PCM or unplugging the battery) in between.

For some people who are constantly flashing in a tune and making changes to their cars, or for those of you who put very few miles on the car each year, this can be a major nuisance should you need to diagnose the vehicle or require the car to have the monitors in a ready state.

Below will show you how to set your sensors to a readiness state.

*** Disclaimer*** DO NOT USE THIS INFORMATION TO CHEAT EMISSIONS. CHEATING EMISSIONS IS ILLEGAL. USING THE BELOW INFORMATION FOR ILLEGAL PURPOSES MEANS YOU ARE DOING SO AT YOUR OWN RISK. PLEASE CHECK WITH YOUR LOCAL PROVINCIAL OR STATE LAWS BEFORE MODIFYING YOUR VEHICLES TUNE. WE ARE NOT RESPONSIBLE FOR DAMAGES OR COSTS INCURRED BY FOLLOWING THE BELOW GUIDE.

***Side note*** It has come to our attention recently that some of the newer Ford Mustangs and F-150s are not able to preform the below operations. As this is due to programming that Ford has in their factory PCM’s some may work, others may not depending on what software is installed on your vehicle. While the below has worked on many GM’s, please be aware that your vehicle may have issues. As we are not affiliated with this product, please visit the hp tuners website and utilize their forums for any questions you may have regarding your vehicle,  use of features and compatibility of their products. The below guide is meant to assist and share knowledge and should not be confused with a sales pitch for hp tuners products.

First step in setting all sensors to ready is to verify which sensors your vehicle checks for, to do so, put the keys in your ignition, plug in your HP Tuners interface, start-up your VCM scanner, start your vehicle and begin scanning. Open your DTC tab as shown below and click the check mark to scan for readiness and DTC codes.

Readiness Sensors unready
Note how my particular vehicle has 3 sensors highlighted in red showing that they are unready? These are sensors that require a drive cycle to be completed in order to set them to a ready state, or you can force the situation with hp tuners.

Once you have identified which sensors your vehicle is looking for, (the ones that say either complete/incomplete only) you will have an idea of which codes you need to set to “No Error Reported” in your DTC list.

Take note, you don’t have to modify anything for the continuous tests so long as they already show complete, this is because regardless of whether you pull the battery and reset the pcm, your car will immediately check/run those tests the moment the car is started back up.

Alright, according to my above picture for my particular car, I am looking for all my O2 sensor and EGR related DTC/trouble codes. I’ve located them below:

O2 sensor DTC
Located the O2 sensors. Notice how I have changed them to “No error Reported” and left them checked to show an SES light? This is how you get the sensor to show as complete/ready status

I did the same thing for my EGR sensors, although they are not pictured above.

After you have have put the relevant sensors to “No error reported” do a “write calibration only” to program your tune into the pcm.

**Note: DON’T get lazy with setting your sensors to No error reported. You DO NOT want to set every DTC for every sensor in your car to No error reported. Sensors such as the MAF being set to this setting could cause the car to not run or go into limp mode. Only select those sensors which are relevant to the readiness tests which are listed in the “once per trip test window”

missed a few sensors
As you can see, after writing in the new tune, I have 2 complete readiness monitors and 1 incomplete. The reason for this is that I missed some of the O2 sensor DTC’s when I went through the list. No big deal, I’ll go back and find it.
O2 sensor No error
Found the rest of the O2 sensor DTC’s. Note that there are quite a few of them. Change all of them to no error reported

Alright, that should cover the remaining O2 sensors that were missed. Go ahead and re-write the pcm again with the new tune.

Write calibration only
Just showing a successful write, it takes about 36 seconds and all readiness monitors should be good to go. A lot quicker than you could drive through a drive cycle.
Readiness sensors ready
Success! All readiness sensors are now good to go.

For the record, in the above photo, I had unplugged the EGR just to prove that even with sensors not hooked up, by setting the DTC’s to no error reported, the ready monitors will show as complete and ready.

All right, now lets write the old tune back in (that you originally saved before you did this) and watch the sensors go back to incomplete.

writing the old test back in
Back to an incomplete state.

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64 thoughts on “Readiness Sensor Tuning”

    • The software I am aware of and used is mainly for American cars- there may be something similar for Toyota available somewhere though!

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