SYS.OK|MANUAL.DB● LIVE
HOMESERVICE MANUALSCHEVROLET1993SPORTVAN G30, VAN PASSENGER, 7.4 NREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 23 (ENGINE CONTROLS - TESTS W/CODES - 6.5L DIESEL)DTC 49 - MIL (SERVICE THROTTLE SOON LIGHT) CIRCUIT FAULTNOTES
1993 Chevrolet Sportvan G30, Van Passenger, 7.4 N

DTC 49 - Mil (Service Throttle Soon Light) Circuit Fault: Notes

1993 Chevrolet Sportvan G30, Van Passenger, 7.4 NSECTION Notes
WARNING: This page does not describe the selected car, but rather 10 other vehicles, including the 1994 GMC Yukon, 1994 GMC Suburban, 1994 GMC Pickup, 1994 GMC Cab & Chassis, and 1994 GMC C3500 HD. However, it is still accessible from the selected car via links, so may be relevant.

The SERVICE THROTTLE SOON light should always light when the ignition is on and the engine is not running for 2 seconds. The PCM controls the MIL and makes it light by providing a ground path. DTC 49 will set when:

  • Ignition voltage on the SERVICE THROTTLE SOON light control circuit when the PCM is requesting the SERVICE THROTTLE SOON light on.

Or 

  • No ignition voltage on the SERVICE THROTTLE SOON light control circuit when the PCM is requesting the SERVICE THROTTLE SOON light off.

PCM will default to the MIL will not light, but a current and history DTC 49 will set.

NOTE: Test numbers refer to numbers on diagnostic chart.
  1. This step checks the PCM's ability to command the SERVICE THROTTLE SOON light.
  2. This step determines if an open is present in the ignition feed circuit or the SERVICE THROTTLE SOON light control circuit.
RENDER: 1.0x

NO RELATED

Recommended Tools & Savings

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Affiliate disclosure: We may earn a commission at no extra cost to you.

Shop Manual-Ready ToolsFree Quote CheckQuote Shield Pro

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.