5 Volt Reference 1 Circuit
2014-2016 Chevrolet Spark EV Electric Motor
Description
The PCM detected that the 5-volt reference A circuit voltage is out of tolerance. This circuit provides the sensor feed voltage for multiple sensors including the MAP sensor, TP sensor, EGR valve position sensor, and fuel tank pressure sensor. A fault here can affect multiple systems simultaneously.
Symptoms
- Check Engine Light
- Engine stalling
- Rough idle
- Poor performance
- Multiple sensor codes may set
- Loss of power
Common Causes
- Short to ground in one of the sensors connected to the 5V reference
- Damaged sensor wiring
- Faulty sensor drawing excessive current
- Defective PCM 5V reference driver
- Fuel pump harness shorted to fuel tank pressure sensor
Diagnostic Steps
- Measure 5V reference voltage at multiple sensors
- Disconnect sensors one at a time to isolate short
- Inspect fuel pump harness for shorts to FTP sensor
- Check sensor wiring for chafing or damage
- Test PCM 5V reference output
Repair Notes
Disconnect sensors one at a time to find which sensor circuit is pulling the reference low. Inspect fuel pump harness. Repair shorted wiring. This is a root-cause code that can trigger many other sensor DTCs.
Related Codes
Other Powertrain Codes
- P0070Ambient Air Temperature Sensor Circuit
- P0071Ambient Air Temperature Sensor Range/Performance
- P0072Ambient Air Temperature Sensor Circuit Low
- P0073Ambient Air Temperature Sensor Circuit High
- P0115Engine Coolant Temperature (ECT) Sensor 1 Circuit
- P0116ECT Sensor 1 Circuit Range/Performance
- P0117ECT Sensor 1 Circuit Low Input
- P0118ECT Sensor 1 Circuit High Input
- P0119ECT Sensor 1 Circuit Intermittent
- P0125Insufficient Coolant Temperature for Closed Loop Fuel Control
P1635 on Other Vehicles
Chevrolet Astro
1995-2005 4.3L V6 Vortec
Chevrolet Avalanche
2002-2006 5.3L V8 Vortec
Chevrolet Avalanche
2002-2006 8.1L V8 Vortec
Chevrolet Avalanche
2007-2013 5.3L V8 Vortec
Chevrolet Avalanche
2007-2013 6.0L V8 Vortec
Chevrolet Aveo
2012-2018 1.6L I4
Chevrolet Beat
2018-2021 1.2L I4
Chevrolet Beretta
1990-1996 2.2L I4
Common Questions
What does code P1635 mean on a 2014-2016 Chevrolet Spark EV?
P1635 stands for "5 Volt Reference 1 Circuit". The PCM detected that the 5-volt reference A circuit voltage is out of tolerance. This circuit provides the sensor feed voltage for multiple sensors including the MAP sensor, TP sensor, EGR valve position sensor, and fuel tank pressure sensor. A fault here can affect multiple systems simultaneously.
What are the symptoms of P1635 on a Chevrolet Spark EV?
Common symptoms of P1635 include: Check Engine Light, Engine stalling, Rough idle, Poor performance, Multiple sensor codes may set, Loss of power.
What causes P1635 on a 2014-2016 Chevrolet Spark EV?
Common causes of P1635 include: Short to ground in one of the sensors connected to the 5V reference, Damaged sensor wiring, Faulty sensor drawing excessive current, Defective PCM 5V reference driver, Fuel pump harness shorted to fuel tank pressure sensor.