What Does P06B8 Mean?
The PCM has detected an error in its internal Non-Volatile Random Access Memory (NVRAM), which stores learned values such as fuel trims, idle speed adaptations, and transmission shift adaptations. When NVRAM is corrupted, the PCM loses all its learned calibration data and must relearn them, potentially causing rough running, poor shift quality, and reduced fuel economy during the relearning period.
Common Causes
35%
PCM internal NVRAM chip degradation or end-of-life failure
25%
Battery voltage drop or interruption during a PCM write cycle corrupting stored data
20%
Incomplete or interrupted PCM reprogramming/reflash corrupting memory
15%
Electrical spike or overvoltage event damaging NVRAM cells
5%
PCM connector intermittent power connection causing write errors
Diagnostic Steps
1
Clear the DTC and drive the vehicle through a complete drive cycle — if the code does not return, the NVRAM error may have been a one-time corruption event that self-corrected.
2
Check battery condition with a load tester — verify at least 12.4V resting voltage and 9.6V or higher under load for 15 seconds. Weak batteries cause voltage dips during cranking that corrupt NVRAM.
3
Verify the charging system output (13.5V-14.7V) and check for AC ripple (less than 50mV) — a failing alternator diode can corrupt memory.
4
Inspect PCM power and ground circuits for intermittent connections — wiggle test connectors while monitoring PCM voltage with a DVOM.
5
If the code returns after clearing, attempt a full PCM reflash with the latest manufacturer calibration. If NVRAM errors persist after reflash, the PCM memory hardware has failed and the module must be replaced.
Estimated Repair Cost
$100 - $1,500
Parts + labor, varies by vehicle and location
The PCM has detected an error in its internal Non-Volatile Random Access Memory (NVRAM), which stores learned values such as fuel trims, idle speed adaptations, and transmission shift adaptations. When NVRAM is corrupted, the PCM loses all its learned calibration data and must relearn them, potentia...
The most common cause of P06B8 (Internal Control Module Non-Volatile Random Access Memory (NVRAM) Error) is: PCM internal NVRAM chip degradation or end-of-life failure
Typical repair costs for P06B8 range from $100 to $1,500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
The vehicle will generally run but may exhibit rough idle, poor fuel economy, and harsh transmission shifts while the PCM relearns its adaptive values. Driving is acceptable for short distances, but if the code recurs after clearing, the PCM may eventually fail completely. Schedule diagnosis promptly.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P06B8 to identify the root cause.
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Quick Info
Category
Powertrain
System
Engine Control Module
Difficulty
Type
Generic (SAE)
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