PCM Memory Performance (Long Term Memory Error)
2014-2016 Chevrolet Spark EV Electric Motor
Description
The PCM detected an internal memory fault in its EEPROM (Electronically Erasable Programmable Read Only Memory). The PCM stores critical adaptive and calibration data in this memory.
Symptoms
- Check Engine Light
- Various drivability issues
- Possible stalling
- Possible no-start condition
- Loss of learned values
- Erratic behavior
Common Causes
- Internal PCM/ECM failure
- Low battery voltage during operation
- Battery disconnection during critical write operation
- Corrupted PCM software/calibration
- Aftermarket tuning device issue
Diagnostic Steps
- Check battery voltage and charging system
- Attempt PCM reflash/reprogram
- Check for aftermarket tuning devices
- Test PCM with factory scan tool
- Verify PCM software version
Repair Notes
Try PCM reprogramming first. If memory error persists, replace PCM. Ensure battery is fully charged before any PCM service.
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
P1621 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 P1621 mean on a 2014-2016 Chevrolet Spark EV?
P1621 stands for "PCM Memory Performance (Long Term Memory Error)". The PCM detected an internal memory fault in its EEPROM (Electronically Erasable Programmable Read Only Memory). The PCM stores critical adaptive and calibration data in this memory.
What are the symptoms of P1621 on a Chevrolet Spark EV?
Common symptoms of P1621 include: Check Engine Light, Various drivability issues, Possible stalling, Possible no-start condition, Loss of learned values, Erratic behavior.
What causes P1621 on a 2014-2016 Chevrolet Spark EV?
Common causes of P1621 include: Internal PCM/ECM failure, Low battery voltage during operation, Battery disconnection during critical write operation, Corrupted PCM software/calibration, Aftermarket tuning device issue.