StandaloneHarness.com Diagnostic Form (copyright 2019)
Step 1 - Print this page so you can make notes. (You may need to copy/paste the text to print everything)
Step 2 - Scan for fault codes. If codes are present list them below in order with the number and description. Listing in order is important as they are prioritized in the ECM from most to least important.
Step 3 - Go to Scanner Live Data Screen (All values come from OBD Port scanner only. No volt meter tests or guessing)
Step 4 - Enter the Actual Values from Scanner Live Data next to the headings listed below. Every heading requires a response unless it's N/A for that particular engine.
Step 5 - Scan this page or take a very clear picture and email the .JPG or .PDF to firstname.lastname@example.org
Engine Year and RPO Code (eg. 2006 LBZ)
Voltage (Key On)
Voltage (While Cranking)
TPS (Throttle Position) (can be a percentage or a voltage)
Yes or No TPS change with Pedal Movement?
APP (Accelerator Pedal Position) (can be a percentage or a voltage)
Yes or No APP change with Pedal Movement?
MAP (Manifold Absolute Pressure)
MAF (Mass Air Flow) (Lightly blow air on the sensor to see if responding)
IAT (Intake Air Temp)
ECT (Coolant Temp)
EOP (Engine Oil Pressure) (Or change when Cranking?)
Fuel Rail Pressure (Desired) Gauge is only OK for LS. Duramax and Gen 5 must be read on scanner.
Fuel Rail Pressure (Actual) Gauge is only OK for LS. Duramax and Gen 5 must be read on scanner.
Fuel Rail Pressure (While Cranking) Gauge is only OK for LS. Duramax and Gen 5 must be read on scanner.
FRT (Fuel Rail Temp) – Duramax
IAT 2 – Duramax
RPM – (Should be 150 during cranking)
CAM Signal – (advanced scanner required)
MPH or KPH while idling in Park or Neutral.
List all OBD “P” Fault Codes in order with Description (required)