Powertrain, generic · Computer and auxiliary outputs

P064C Glow Plug Control Module 1

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

On diesels a glow plug control module switches the glow plugs (at Ford also the DEF heaters) with semiconductor switches, diagnoses itself and reports to the engine module. P064C means this module reports an internal fault. GM's 2017–18 Duramax checks for a switch that is commanded on but delivers less than 3.2 A and 0 V at the plug (3.5 s), ROM, RAM and EEPROM checksums, the charge pump of the high-side drivers and reverse polarity; the LML (2011–16) used under 6.6 A for 75 % of 4 s; lamp after two trips. Ford's 2023 diesels flag drivers that do not switch or overheat, a RAM checksum error, supply below 6.5 or above 16.5 V and module temperature above 125 °C, within about 1 s. The glow system then fails partly or completely: hard cold starts, white smoke and higher cold-start emissions.

Likely causes

Glow plug module faulty internally (switches, memory)
Insufficient supply or ground (battery, corrosion, main fuse)
Short in a glow plug or wire overloading a driver
Moisture or corrosion in the connector of the engine-mounted module

Symptoms

  • Check engine and glow plug lamp
  • Hard cold start, long cranking in cold weather
  • White smoke and rough running after a cold start
  • Glow plug circuit codes as well

Repair estimate

DifficultyMediumDIY possible
Parts and labour€150–600
Time0.5–2 h

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

Parts involved

glow plug control moduleglow plugsmodule power supply

Related codes

P0670P0671P0381P06DFP06E5P263E

References: law.cornell.edu, gsi.ext.gm.com, gsi.ext.gm.com, fordservicecontent.com.