Powertrain, generic (extended)

P2E74 Hybrid/EV Battery Pack Coolant Temperature Sensor D Circuit

Check engine lightOn

EmissionsRelevant

Drive cycleNot required

Limp modePossible

P2E74 covers any circuit fault of coolant temperature sensor D, the fourth such sensor a maker can fit to the battery's liquid cooling. Battery controllers typically watch coolant at the pack inlet and outlet; GM's Volt and ELR tables use sensor A for the inlet and B for the outlet. Where a sensor D sits is not public. No manufacturer documents P2E74 publicly. Such sensors are sealed NTC thermistors; one supplier part for battery coolant reads 2828 ohms at 25 °C. GM's 2011 Volt runs its coolant sensor range checks only while no fault is active on the battery controller's 5 V reference circuit. CARB requires the inputs of battery heating and cooling to be monitored. Without the value, cooling may run on substitute data and power can be limited.

Likely causes

Damaged wire, loose connector or corroded terminal at sensor D

Fault on the shared 5 V reference circuit of the battery controller

Coolant temperature sensor D failed

Symptoms

Hybrid system or check engine light
Battery cooling or heating not working as intended
Reduced electric power or charging rate

Repair estimate

DifficultyHardWorkshop job

Parts and labour€80–700

Time0.5–4 h

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

Parts involved

hv battery pack coolant temp sensor dwiring harnessbms

References: law.cornell.edu, amphenol-sensors.com, en.wikipedia.org, gsi.ext.gm.com.