MAP Controlled Engine Cooling Thermostat, Checking

Map controlled engine cooling thermostat, checking

Recommended special tools and equipment
- VAG1526 multimeter or VAG1715 multimeter
- VAG1594 connector test kit
- Wiring diagram

Test requirements







The respective fuses of Motronic Engine Control Module (ECM) -J220- must be OK.







- Fuses -1, 2, 3, 4 and 7- in protective housing (plenum chamber, left) must be OK.
- Ground (GND) connections between engine and chassis must be OK.
- Coolant temperature must be approx. 25 degrees C, Diagnostic mode 1: Check measuring values; PID 5, Coolant temperature. Diagnostic Mode 1: Check Measuring Values
- Ignition switched off.

Test sequence
- Remove intake air hose between Mass Air Flow (MAF) sensor and throttle valve control module, item 1 .
- Remove upper part of intake manifold (with both intake manifold side parts), item 8 .


NOTE: When removing the upper part of the intake manifold, ensure that the alignment pins are positioned in lower part of the intake manifold and do not fall into the intake channels!


- Remove lower part of intake manifold, item 13 .


NOTE: Seal the intake channels in cylinder head using a clean rag.







- Disconnect 2-pin connector from Map Controlled Engine Cooling Thermostat -F265- (arrow).

Checking resistance
- Measure resistance between terminals of thermostat.
Specified value: 14.0...18.0 Ohms

If specified value is not obtained:
- Replace Map Controlled Engine Cooling Thermostat -F265-.
- Erase DTC memory of Engine Control Module (ECM), Diagnostic mode 4: Reset/erase diagnostic data.
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes

If specified value is obtained:

Checking wiring
- Connect test box to control module wiring harness, connect test box for wiring test. Test Box, Connecting For Wiring Test







- Check wire between test box socket 116 + 2-pin connector terminal 2 for open circuit according to wiring diagram.
Wire resistance: max. 1.5 Ohms
- Also check the wire for short circuit to B+ and Ground (GND).
Specified value: Infinity Ohms
- Check wire between 1-pin connector terminal 2 and the relay carrier for open circuit according to wiring diagram.
Wire resistance: max. 1.5 Ohms
- Erase DTC memory of Engine Control Module (ECM), Diagnostic mode 4: Reset/erase diagnostic data.
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes

If no malfunctions are detected in the wires and the resistance value is OK:
- Replace Motronic Engine Control Module (ECM) -J220-.