Powertrain, generic · Computer and auxiliary outputs

P06A8 Sensor Reference Voltage C Circuit Range/Performance

Check engine lightOn

EmissionsRelevant

Drive cycleNot required

Limp modePossible

The engine module feeds sensors from several regulated 5 V reference circuits; a short at one sensor pulls the whole circuit down and all its sensors report at once – unplug them one by one to find the culprit. P06A8 is the range/performance check of reference circuit C, without separate low and high codes. Ford uses it: its 2012 and 2020–23 petrol tables flag below 4.7 V or above 5.2 V for 0.5 s (Bosch modules), the 2023 diesel supply 3 below 4.7 V or above 5.3 V; in Ford's DPS6 transmission module it monitors the output speed sensor supply. GM uses the collective code P0697 for circuit C instead.

Likely causes

Short in the wire or sensor of a connected sensor

Chafing or water in harness or connector

A connected sensor faulty internally

Module internal voltage regulator or components

Symptoms

Check engine light
Several sensor codes at once
Reduced power or limp mode
Possibly starting problems

Repair estimate

DifficultyMediumWorkshop job

Parts and labour€80–600

Time1–3 h

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

Parts involved

sensor reference voltage circuitsensor wiringengine control module

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