Howdy!
First time poster, I have a 99 Express 1500 5.7. Drove it for awhile before the pandemic then let it sit on a battery tender while the world fell apart...

Recently went to get it running again for a van-life build and holy moses it tossed 40 codes! I generally work on Toyota's and VW's so this is a bit new to me. When I first got it, I replaced the coolant system and all 4 O2 sensors. It still runs like a top but these codes are scaring me!
Battery Reads 12.4V off and 13.8V Running.

P1345 Crankshaft Position Sensor (I understand this could be due to a timing issue related to the distributor)
P135 Heated O2 Sensor Heater Performance B1S1
P0121 TP Sensor Circuit Inactivity
P0131 O2 Sensor Voltage B1S1
P0133 O2 Sensor Slow Response B1S1
P0134 O2 Sensor Insufficient Activity B1S1
P0137 O2 Sensor Low Voltage B1S2
P0138 O2 Sensor High Voltage B1S2
P0140 O2 Sensor Insufficient Activity B1S2
P0141 O2 Sensor Heater Performance B1S2
P0151 O2 Sensor Low Voltage B2S1
P0153 O2 Sensor Slow Response B2S1
P0154 O2 Sensor Insufficient Activity B2S1
P0155 O2 Sensor Heater Performance B2S1
P0157 O2 Sensor Low Voltage B2S2
P0158 O2 Sensor High Voltage B2S2
P0160 O2 Sensor Insufficient Activity B2S2
P0161 O2 Sensor Heater Performance B2S2
P0171 Fuel Trim System Lean B1
P0172 Fuel Trim System Rich B1
P0174 Fuel Trim System Lean B2
P0175 Fuel Trim System Rich B2
P0325 PCM Knock Censor Circuit
P0327 Knock Sensor Low Voltage
P0401 EGR Flow Insufficient
P0404 EGR Open Position Performance
P0420 Catalyst System Low Efficiency
P0430 Cat. Low Efficiency B2
P0440 Evap System
P0442 Evap System Small Leak Detected
P0446 Evap Vent Solenoid Valve Control System
P0461 Fuel Level Sensor Circuit Performance
P0500 Vehicle Speed Sensor (VSS) Circuit
P0502 VSS Circuit Low Input
P0503 VSS Circuit Intermittent
P0560 System Voltage
P0601 Control Module Read Only Memory (ROM)
P0603 Control Module Long Term Memory Reset
P0604 Control Module RAM
P0605 CM Programming ROM
P0724 Brake Switch High Voltage

Not sure how I can have Low and High Voltages and Rich and Lean conditions all at the same time?? Someone please tell me it's just the Battery or the Computer that needs to be replaced! I'm about ready to over-insure this thing and drive it off a cliff! Thanks!

 

it's just electrical glitches from unstable power.
Get your alternator + battery load tested (free @ Autozone), and replace as necessary.
Clear the codes, and see what comes back after that.

 

More than likely it needs a new battery.

 

with all those codes to be showing , after the battery load test, I'd check and clean the ground(s) too.

 

Yes, the ground strap on the bottom is known for corroding and crumbling apart

 

on my 07 3500 , cleaning then replacing the ground straps helped a lot. afterwards, got much cleaner signal voltage patterns, which helped to eliminate what might be going wrong to cause the persistent p0300 random cyl misfires.

 

if i m not wrong its battery issue

 

Big thanks for all the replies! I did exchange the battery for a new one. The girl at the auto-parts store was in disbelief that it actually started the van at all!
Turns out the P1345 Crankshaft Position Sensor code was legit. Luckily I have Torque Pro on my phone and was able to find the formula for Cam Position Retard Offset.
CMPRET was at -6.1 degrees, I was able to reset the distributor to factory specs, 0 degrees +/- 2 at 1000rpm.

If anyone wants the formula for the future, here it is:
In Torque Pro tap Settings (Gear Icon)
Manage extra PIDs/Sensors
Press Menu to Add Custom PID

OBD2 Mode and PID: 221301

Long Name: Cam Position Retard Offset

Short Name: CMPRET

Minimum Value: -100

Maximum Value:100

Scale Factor: x1

Unit Type: degrees

Equation: ((Signed(A)*256)+B)*0.024)

OBD Header to use: 6C10F1

Diagnostic Start: blank
Diagnostic Stop: blank
Minimum refresh delay: 0
Overrides PID: Does not override
Remember equation function data: Store value in vehicle profile

Click OK

 

Wow, that's quite a laundry list of trouble codes! It's understandable to feel overwhelmed, especially with so many codes indicating various issues. However, it's unlikely that all these problems are occurring simultaneously.

 

Hey! I also think that you should try disconnecting and reconnecting the ECM because this can really solve some electronic issues.

If after doing this, the issues persist, consider the possibility that the ECM itself might be acting up, especially with those memory and ROM errors.
For the P0724, this brake switch trouble code guide might help you.