The P0653 code in your 2019 Chrysler 300 indicates that the sensor reference voltage A circuit is reading higher than expected. Instead of the normal 5 volts, the circuit shows elevated voltage that exceeds specifications. This unusual condition affects sensor accuracy and can cause various engine management issues.
Understanding High Reference Voltage
The ECM's reference voltage regulator should produce precisely 5 volts. If it produces higher voltage, sensors report inaccurate readings because their calibration assumes 5 volts. High voltage can also damage sensitive sensor electronics over time. This condition is less common than low voltage issues.
What Causes High Reference Voltage
An internal ECM regulator failure that produces excessive voltage is one cause. A short to a higher voltage source in the wiring can inject unwanted voltage into the reference circuit. Certain sensor failures can feed voltage back into the reference circuit. Improper repairs that connected the reference line to battery voltage cause immediate high readings.
Symptoms in Your Chrysler 300
Sensors may report readings that are too high or out of range. Engine performance issues arise from incorrect sensor data. Multiple sensor-related codes may accompany P0653. The ECM may enter a protective mode, limiting engine operation. The check engine light illuminates with this code stored.
Diagnostic Steps
Using Chrysler wiTECH, measure the actual reference voltage at the ECM output. Normal is 5.0 volts ± 0.1 volt. If voltage is genuinely high, check for improper wiring repairs or connections that might introduce external voltage. Inspect individual sensor connections for cross-wiring. If the ECM's regulator is producing high voltage internally, the module may need replacement.