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Home >> Volvo >> 2003 >> C70 2.3 53, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 93 (Electronic Climate Control (ECC), Manual Climate Control (MCC), Heater Module (HEA) - Diagnostic Trouble Code (DTC) Diagnostics - 2 Of 2 (Coupe)) >> HEA-801: Coolant Temperature Sensor. Signal Too High (1999-2002) >> Signal Too High >> Intermittent Fault

Intermittent Fault

WARNING: This page is about a different car, the 2002 Volvo C70, 2001 Volvo C70, 2000 Volvo C70, 1999 Volvo C70, and 1998 Volvo C70. However, it is still accessible from the selected car via links, so may be relevant.

Check control module connector for contact resistance and oxidation in accordance with Contact Resistance And Oxidation .

Check circuit for an intermittent open-circuit by measuring resistance between control module connector #16 and #4 (towards the sensor) and follow the instructions according to Open-Circuit, Intermittent Faults . Resistance should be according to Component Resistance Values .

Check cable between control module #16 and engine coolant temperature sensor for an intermittent short-circuit to supply voltage according to Short-Circuit To Supply Voltage, Intermittent Faults .

Remedy as necessary.

Other information: 

Fig 1: Identifying Data Link Connector
GLL102417Courtesy of VOLVO CARS OF NORTH AMERICA.
Fig 2: Identifying Ohmmeter
GLL101042Courtesy of VOLVO CARS OF NORTH AMERICA.
Fig 3: Identifying Coolant Temperature Sensor Circuit
GLL102411Courtesy of VOLVO CARS OF NORTH AMERICA.