2004 Silverado 1500 emissions not ready

Luke Morgan · January 20, 2017

My truck won't pass emissions. It shows "not ready" for the Evap system, catalyst, and an o2 sensor. I drove it for about 500 miles between tests. I got looking at the vehicles history and it looks like the "not ready" issue has been ongoing for this truck? Any ideas?

Chris · January 20, 2017

There is a drive cycle that has to be followed to make them set and it is a pain in the ass. Look it up. Try it. If that doesn't work I don't know. I've tested with the Evap not ready.

working on it · January 21, 2017

There is a drive cycle that has to be followed to make them set and it is a pain in the ass. Look it up. Try it. If that doesn't work I don't know. I've tested with the Evap not ready.

I had multiple problems to solve before my HHR was ready to test. I had parked it a year earlier, when the sticker expired. I fixed ABS sensor, MAP sensor, fuel cap leak, and finally the Evap vent solenoid. I had to restart the DRIVE CYCLE 5 times before I was done, and even so, I couldn't get the EVAP not ready to go away. Total 1100 miles; 200 after last repair. Texas passed it with the Evap still unset. I followed this Drive cycle : Good luck with your problem; I just got a P0135 code this afternoon, as well, on my '04 2500HD. I cleared the code, and will see if it sets again. I have 8 months to complete that next drive cycle!

Chris · January 21, 2017

Some scanners can force to evap leak test

working on it · January 22, 2017

Some scanners can force to evap leak test

Not any of mine. I started with scanning apps: Torque Pro, then OBDWiz using two OBD dongles : a BAFX then an OBDLink LX (used the BAFX until I needed the LX to use the OBDWiz app). Both pps & dongles use a smartphone or tablet to give me the live data and OBD readiness status. I bought an Innova 3100i scan-tool to verify the apps' data, and to read my ABS faults (the apps cannot), I bought the 3100i for cheap ($75), but wish I'd ante'd up another $100 to get the 3130 bidirectional tool. That one will run the EVAP test.

5829BMG · January 23, 2017

Drove one 600 miles and couldn't get it ready. Disconnected the battery touched the two terminals together to drain capacitors then reconnected and drove 10 miles trying to follow drive cycle as best as possible and it passed all systems ready. Try it and see what happens.

Chris · January 23, 2017

Not any of mine. I started with scanning apps: Torque Pro, then OBDWiz using two OBD dongles : a BAFX then an OBDLink LX (used the BAFX until I needed the LX to use the OBDWiz app). Both pps & dongles use a smartphone or tablet to give me the live data and OBD readiness status. I bought an Innova 3100i scan-tool to verify the apps' data, and to read my ABS faults (the apps cannot), I bought the 3100i for cheap ($75), but wish I'd ante'd up another $100 to get the 3130 bidirectional tool. That one will run the EVAP test.

I have the 3160d. I think I got it for $90 on amazon a couple years ago

working on it · September 23, 2022

On 1/20/2017 at 7:11 PM, Chris said:

Some scanners can force to evap leak test

Welp, you're right; five years later, I finally have a scantool that will force the Evap test (but the I/M monitor still shows Evap as incomplete, though the "tests" all reported "ok"). I used a Foxwell NT510 Elite, that I bought with dual programming (for GM and BMW) in January '21. First time I tried it on the 2500HD, though. I'm about to get the yearly inspection on Monday or Thursday, so I was checking the monitors (one incomplete monitor is OK in Texas), so I scanned/tested the truck today.

It showed nine powertrain faults, of which none showed up on my Innova 3100i scantool. Some of them were evap codes (there before I fiddled with the active tests), some were cruise control (which I added years ago, so the ECM might not recognize), and a few were transmission-related (I have first gear slippage starting); of course I wanted to, but couldn't clear them, fearing a repeat of the extended drive cycle nightmare I had in 2017. I'll clear them after the inspection!

Edited September 23, 2022 by working on it