I have a 1997 that has a check engine light that is driving me crazy. I could not get the car to pass Texas State emissions inspection. I parked the car and did the following The car has 145,000 miles on it. Headers and a tune.
I just replaced both Air Check Valves, Knock Sensors Oil Pressure Sending unit along with all injectors 24LB. Car runs like a champ Check engine light was off drove it for about 10 minutes pulled over to set radio settings and at an idle the check engine light comes back on.

Went home and checked codes:
PCM P0410HC
LDCM and RDCM codes #1 Circuit and #2 Circuit
SCM B0851H Battery out of range
RFA U1255H Serial Data Line malfunction

There are a few other codes but they are related to the HVAC and BCM codes

What do I need to check next or replace. With out a laptop I can not get in to turn off codes.
I just want to drive it like ai stole it once again.

 

Welcome to the Corvette Forum !!...first off I’d worry about the P0410 first...highly doubtful both check valves could have gone bad at the same time to set the DTC...without a bi directional scan tool or a Tech 2 this may be a little difficult to diagnose...you can have a bad pump or solenoid...does the AIR pump run when the car is first started in the morning ??...if you open the hood and put your ear near the drivers headlight you can hear the pump run for about 20 seconds or so and then shut off...the pump may also not be putting out the volume of air it should have...if not you can check AIR PUMP relay #33...try swapping the relay with another such as the horn relay and see what happens...as far as the solenoid you can see if you have power at the pink wire...fuse 50 is also for the pump... check that !!...The solenoid (above the PCM) get power when the key is in ON or START through ignition relay 42...the PCM provides the ground for the solenoid to work...there is also a vacuum operated shut off valve that opens once the solenoid is energized and allows the air from the pump to flow into the exhaust manifolds...with the 2 scan tools I mentioned you can command the PCM to provide that ground and makes it very easy to diagnose this DTC !!

 

First you have a voltage issue with the car. There are at least three codes related to voltage issues, the two door issues and the battery code.

Fix your voltage issue and the other issues may go away.

Bill

 

GREAT advise !!...many DTC’s can indeed be caused by low voltage...even misfires !!...my Picoscope has a great starting and charging system test that I always do and print out for any car that I may look at !!

 

Great Info, I will try that or get a Tech II tool.

 

Clean the battery terminals

 

Do they do visual inspection on OBD2 cars in Texas? If not, delete the AIR system.

 

they do but most would probably never even notice

 

Did you get the tune before or after headers? Do your headers have an AIR provision? I'm assuming you have no cats?

Pretty sure any tune on a header car would remove any AIR system checks but I'm no tune guru.

 

When I relocated my OPS, I forgot to attached the AIR hose back to the Intake. Instead of removing the intake to attach it I placed a small cap on the Intake inlet and moved the AIR to non reporting in the PCM.

 

https://www.dps.texas.gov/rsd/vi/Mis...ists092005.pdf. This website gives the failure criteria for Texas. It is very close to the NC state requirements.

Basically, you can have one Mode 6 readiness test listed as not ready, and one DTC code showing. You must have two M6’s showing not ready. The only DTC that is relevant to emissions is your P0410. In order for you to see the readiness monitors, you will need a scan tool with at least the capability to see mode 6. The Tech 2 is basically a go-to scan tool. There is a healthy learning curve associated with any scan tool, and besides learning the scan tool, you will need a service manual, and some basic knowledge of the system throwing the specific DTC.

The AIR system, in your case, has a small electric air pump to the left of the radiator and it draws filtered air from the air filter box. Certain driving conditions, closed loop, etc have to be met, and a puff of air is sent into the exhaust upstream of the O2 sensor. This adds a tad bit of oxygen to the exhaust stream, causing a slight lean condition to be detected by the O2 sensor.

Your pcm looks for this change, and if it sees the O2 sensor response and will be “happy”. If it does not see this change then the DTC P0410 is set. Now at this point some folks would start replacing air parts and O2 sensors( not a sure fire fix to say the least). Here’s where the learning curve starts. With a good scan tool, you can activate components and watch for the response. Many of the aftermarket scan tools have the ability to display graphically so you can watch O2 sensor response and use bi-directional control to turn on the AIR . From there the trouble shooting begins

While the Tech 2 is good, the ability to graph and view multiple PID’s is limited.

 

97 can have 2 "not ready", 01+ can only have 1

 

Rather than waste your time fixing the AIR system, just remove it and tune out the codes. Even with a visual inspection, it's unlikely that anyone would ever know you removed the AIR system.