VOLVO
DEM-P188A68 - Differential Oil Temperature Too High/Too Low. Algorithm Based Failures. Event information
System
Differential Electronic Module (DEM)
Volvo models this fault code applies to
Applies to the following models:
4 modelsS80 (2007–), V70 (2008–), XC70 (2008–), XC90 (2003–)
Show models by year and engine (9)
- Volvo S80 (2007–)2007–2008
- Volvo V70 (2008–)2008
- Volvo XC70 (2008–)2008
- Volvo XC90 (2003–)2005Transmission TF-80SC AWD only
- Volvo XC90 (2003–)2006Engine B8444S only · Transmission TF-80SC AWD only
- Volvo XC90 (2003–)2007–2010Engine B6324S, B8444S only · Transmission TF-80SC AWD only
- Volvo XC90 (2003–)2011Engine B6324S5, B8444S only · Transmission TF-80SC AWD only
- Volvo XC90 (2003–)2012Engine B6324S5 only · Transmission TF-80SC AWD only
- Volvo XC90 (2003–)2013–2014Engine B6324S5, D5244T18 only · Transmission TF-80SC AWD only
What does this fault code mean?
Despite the name of the code, it concerns the temperature sensor on the four-wheel drive control module (DEM), which measures the temperature inside the module. The code is set when the signal falls outside the sensor's working range. This is an event-controlled code, meaning it is information that something has happened rather than a fault in the module. If the module gets too hot, four-wheel drive is switched off to protect the components.
Possible causes
- Damaged temperature sensor
- Damaged control module
- Damaged oil pressure or oil temperature sensor
- Too high temperature in the control module
What you can do
- 1Read off the fault code and see whether it is permanent or has cleared. An event-controlled code can appear after a period of high heat
- 2Let the four-wheel drive cool down, then drive the vehicle for a while before checking whether the fault returns
- 3If you have a diagnostic tool, read the control module temperature in live data and check that the value follows how long the vehicle has been driven
- 4Check the connector to the control module for oxidation and loose fit, and make sure the wiring is undamaged
- 5If the fault returns even after the control module has cooled, have a workshop check the control module and the sensor
Symptoms you may notice1
- Four-wheel drive does not work
What the fault can affect1
- Four-wheel drive is disengaged while the fault is present and for a while after it has cleared
General guidance for car owners. Diagnosis on the car can point to a different cause.