Powertrain, generic · Computer and auxiliary outputs

P06B8 Internal Control Module Non-Volatile Random Access Memory (NVRAM) Error

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

Non-volatile RAM keeps its content without power; among other things it stores the permanent fault codes CARB requires, which cannot be cleared with a scan tool. Ford sets P06B8 when the checksum of this permanent-code memory is wrong; a common companion is P068A (main relay dropped out too early, memory write incomplete). Ford's commercial and propane variants list it with or without the check engine light depending on the vehicle; Ford's 2023 diesel table misprints it as 'P068B'. GM and Saab do not use P06B8. Typical causes are interrupted shutdowns (battery disconnected, voltage dips), software faults and, rarely, a memory defect. After a software check, clearing and an ignition cycle with normal shutdown often resolve it.

Likely causes

Interrupted shutdown (battery disconnected, voltage dip, main relay too early)
Engine module software
Weak battery or poor ground
Memory defect in the module

Symptoms

  • Check engine light (depending on the vehicle)
  • Often no driving symptoms
  • Possibly P068A as well

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€0–1,200
Time0.3–3 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

engine control modulecontrol module power supply

Related codes

P062FP0603P0604P0605P068A

References: law.cornell.edu, newtonnet.co.uk, fordservicecontent.com, roushcleantech.com.