Cooling/Heating System - Poor Heater Output/DTC P2181 Set
19 08 092009948/7
November 17, 2008. Supersedes Technical Service Bulletin Group 19 number 07-03 dated April 30, 2007 for reasons listed below.
Vehicle Information
01 Low heater output (DTC P2181)
Condition
Low heater output. DTC P2181 (Cooling system performance) may be stored in DTC memory.
Technical Background
Low heater output may be due to a sticking non-return valve in the hose from radiator to left auxiliary radiator. If the valve is sticking, the engine takes too long to warm up when the outside temperature is below 32 degree F.
Production Solution
Not applicable.
Service
Check coolant flow as follows:
allroad
Figure 1:
1. Check cooling system by clamping off coolant hose (Figure 1) between non-return valve and left auxiliary radiator.
2. With coolant hose clamped off, check engine warm-up performance.
3. If engine warms up faster when coolant hose is clamped off, install new coolant hose with non-return valve (Figure 1).
S4
Figure 2:
1. Check cooling system by clamping off coolant hose (Figure 2) between non-return valve and left auxiliary radiator.
2. With coolant hose clamped off, check engine warm up performance.
3. If engine warms up faster when coolant hose is clamped off, install new coolant hose with non-return valve (Figure 2).
Warranty
Required Parts and Tools
All parts and service references provided in this TSB are subject to change and/or removal. Always check with your Parts Department and service manuals for the latest information.