Hello,

I have a 2019 Suburban LS with 5.3liter engine and 95,000 miles. Regular maintenance performed.
My wife was driving and said there was a loss of power, but it was temporary (for a few seconds, less than a minute), then the truck power returned to normal. I hopped in and drove the truck back home (~30miles highway) and didn't feel anything wrong, no shakes, no check engine light. Curiously enough, once I got to the streets I started to feel some engine power loss, then "reduced engine power" message popped up on the dash. I was able to make it to the driveway, but just before reaching the driveway the power was so low, I basically crawled into the driveway. I turned off the truck, tried to restart it, but ever since then, the truck will turn on somewhat normal, but immediately the RPM are only at ~300RPM, the door chime then starts going off non stop *ping-ping pin*, and the engine dies. There is no throttle response if I try to give it some gas pedal to keep rpms up, they just stay at ~300RPM.
The truck never overheated, never went past center tick on temp, no blue smoke, no sweet smell, coolant doesn't have sign of oil in it, and oil doesn't have coolant in it.
I figured it was about time to replace O2 sensors, and maybe they were the culprit but this didn't make any noticeable difference whatsoever. I checked fuel pressure and fuel pump pressure looks fine, however, I couldn't find what fuel rail pressure range is acceptable for this engine. Checked misfires and found all cylinders are misfiring. Any help would be greatly appreciated.

Current Fault Log
------------------
P1400: [BMW] Heated Catalyst Battery Voltage or Current too Low During Heating (Bank 1)
[Ford] Differential Pressure Feedback Electronic Sensor circuit Low Voltage
[Toyota] Sub-Throttle Position Sensor.
[Nissan] EGRC Solenoid Valve
[Lexus] Sub-TP Sensor Malfunction
[Mazda] DPFE Sensor Circuit Low Input
[Mitsubishi] Manifold Differential Pressure Sensor circuit.
[Seat/Audi/Volkswagen] EGR Valve Circ Electrical Malfunction

U0073: Unknown code - More information may be available on the web

Pending Fault Log
------------------
P0300: Random/Multiple Cylinder Misfire Detected
P0700: Transmission Control System (MIL Request)

Historic Fault Log
------------------
P0106: Manifold Absolute Pressure/Barometric Pressure Circuit Range/Performance Problem
P0107: Manifold Absolute Pressure/Barometric Pressure Circuit Low Input
P0157: O2 Sensor Circuit Low Voltage (Bank 2 Sensor 2)
P0171: System too Lean (Bank 1)
P0174: System too Lean (Bank 2)
P023F: Unknown code - More information may be available on the web
P0452: Evaporative Emission Control System Pressure Sensor Low Input
P0463: Fuel Level Sensor Circuit High Input
P0506: Idle Control System RPM Lower Than Expected
P057C: Unknown code - More information may be available on the web
P12A6: Unknown code - More information may be available on the web
P16A1: Unknown code - More information may be available on the web
P2122: Throttle/Pedal Position Sensor/Switch D Circuit Low Input
P2123: Throttle/Pedal Position Sensor/Switch D Circuit High Input //These in bold were historical due to me removing grounds to clean them, I also unplugged the gas pedal sensor to blow it out with air.
P2127: Throttle/Pedal Position Sensor/Switch E Circuit Low Input
P2535: Ignition Switch Run/Start Position Circuit High
U0101: Unknown code - More information may be available on the web
Other discovered fault codes
(possibly pending, current or manufacturer specific)
----------------------------------------------------
ECU reports no other fault codes logged

End of report.

 

Check fuel pressure.

 

Thanks for the response. However the fuel pressure from the fuel pump looks good. The high pressure side on the fuel rail is around 2k psi. I have the picture posted with actual values

 

Welcome to the forum. Over 2K psi sounds a little suspect to me.

 

Battery condition is the first check. Needs a load test. If it has a weak cell or internal connectors issues it will set all kinds of codes. Shop manual diagnostics list it as it must be in great shape as it's the foundation for the electronics and is the first thing to verify good for multiple code sets. Just because it cranks up doesn't mean its good and if the original it's over 3 yrs old which is average life of one today.

 

@73shark do you know what PSI level the fuel rail should be at? -this far down fuel delivery only has injectors to go through, right? Does this indicate all my injectors clogged at the same time?
@repairman54 I installed a new battery only about 3-4 months ago

any thoughts on what I should check next?

 

With the key on and the engine not running, the pressure should be in the 50 psi range. It should be about the same or perhaps a little higher with the engine running.

 

2019 is a direct injection motor. Lift pump is the low pressure reading, high is the fuel rail pressure after the high-pressure pump that feeds the DI injectors.
There is no cleaning of the throttle pedal sensor, only replacement. They do wear out. Critters can chew harness also, my D in L had that on her Equinox. If MAF code does not go away after cleaning, replace it.

What are the Possible Causes of the P1400 CHEVROLET Code?

• Dirty Throttle Body
• Dirty Air Filter
• Dirty Mass Air Flow (MAF) Sensor
• Intake manifold leak
• Exhaust leak
• Damaged, restricted, modified or enhanced exhaust system

 

**UPDATE**

Hi all,

thanks for the responses. After being stumped on this one I scoured the internet and found a video about checking for clogged cats. I removed the precat o2 sensor from the bank that had most misfires (o2 sensor still connected electrically). Turned the key and turned on no problem. I was able to rev the suburban and while it was loud because of the removed sensor, it ran just fine. I am going to say this is result of a clogged catalytic converter. Any thoughts on this?
I've never had an issue with cats, even after 200k miles on one of my previous vehicles. Is this something common to happen on a newer suburban? This is only a 2019, with less than 100k. Dealer said the cats are covered under warranty up to 50k miles, so out of luck there.
I'd rather not fork out a ton of $$ for this if I don't have to. I've seen there are videos about cleaning catalytic converters, but they have some tiny ones where the cat unbolts on either end, making it easy to slosh around some cleaner. Is this something that can be done on the large catalytic converter on the suburban? Any input would be appreciated.
Also, I'm glad I tried this quick and simple test before removing the intake to check the injectors! Hope this helps anyone who experiences this issue!

 

There is no cleaning cats. Internet fantasy's, they all fail again.
Factory warranty is a federal warranty, 8 years / 80k miles on cats, it's in the owner's manual. A good dealer that you bought new from may back list the mileage to cover you.
Cats can fail, I had a '03 Malibu cat plug up. Only cat issue I ever had in many vehicles.
Mufflers can internally collapse also.
The ''Italian tune up" actually is good for cats. It gets them up to temp to burn off build up. I live near a 2-mile uphill on an interstate and I can tell by the smell who just puts around town and has a dirty cat vs someone who gets on it occasionally when pulling onto and behind them going up that hill.