Diagnostic Aids
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2018 GMC Yukon XL, 2018 GMC Yukon, 2018 Chevrolet Tahoe, 2018 Chevrolet Suburban, and 2018 Cadillac Escalade ESV. However, it is still accessible from the selected car via links, so may be relevant.
Inspect for any of the conditions listed below:
- Insufficient fuel can cause a no start condition. Thoroughly inspect the fuel delivery system for sufficient fuel volume to the fuel injectors. Inspect the fuel supply components for partial blockage or restrictions.
- A stuck camshaft position actuator solenoid valve, which may cause retarded valve timing and low fuel pressure. The engine may sound like it is cranking too fast. A compression test may show low compression and exhaust flow out of the tailpipe may be noticeably less when compared to a known good vehicle. DTC P00C6 may also set. Use the scan tool to cycle the camshaft actuator solenoid valve several times and then try to start the engine. Examine the valve for contamination and clean, if necessary. Perform a dynamic test on the valve to verify correct operation, if necessary - Refer to DTC P0010, P0011, P2088 or P2089 for instructions.
- Fuel injectors with partially blocked and restricted nozzles or a malfunctioning solenoid, can cause a no start condition.
- There may be fuel spray at the fuel injectors and the indicated fuel pressure may be correct, yet there may not be enough fuel to start the engine. If the fuel injectors and the injector circuit are OK and fuel spray is detected, the fuel injector ON time may be inadequate. If the engine control module (ECM) receives incorrect inputs from the various information sensors, the fuel delivered by the fuel injectors may be inadequate to start the engine. Observe all the engine data parameters with a scan tool and compare the values indicated with the expected values or the values from a known good vehicle.
- Observe the Engine Speed parameter while cranking the engine. The scan tool should indicate a steady 200 - 300 RPM while cranking. If erratic values such as sudden spikes in the engine speed are displayed, the engine reference signal is not stable enough for the engine to start and run correctly.
- Inspect the engine for good secure electrical grounds.
- If the engine almost starts and then stalls, inspect for an open in the ground circuits of the CKP sensor and the camshaft position (CMP) sensor.
- Water or foreign material in the fuel can cause a no start or engine will not stay running condition. During freezing weather water can freeze inside the fuel system. The engine may start after 30 minutes in a heated repair shop. The malfunction may not recur until parked overnight in freezing temperatures. Extreme weather conditions can cause contaminated fuel to prevent the vehicle from starting.
- An engine that starts and runs after being brought to the repair shop for a no start condition may have an ignition system that is susceptible to moisture. Spray water on the ignition system components and the wiring while cranking the engine to help locate damaged or deteriorated components. Look/listen for arcing or misfiring as the water is applied.