P1573

DTC P1573 (36, 37): DC-DC Converter Temperature Signal Circuit Problem
1. Reset the MCM.
2. Turn the ignition switch ON (II).
Is DTC P1573 indicated?
YES-Go to step 3.
NO-Intermittent failure, system is OK at this time. Check for poor connections or loose terminals at the DC-DC converter and at the MCM.
3. Turn the ignition switch OFF.
4. Turn the battery module switch OFF.
5. Remove the IPU lid.





6. Check for continuity between body ground and MCM connector terminal C3.
Is there continuity?
YES-Go to step
NO-Go to step 11.
7. Disconnect the DC-DC converter 8P connector.





8. Check for continuity between body ground and MCM connector terminal C3.
Is there continuity?
YES-Go to step 9.
NO-Replace the DC-DC converter.
9. Disconnect MCM connector C (17P).





10. Check for continuity between body ground and MCM connector terminal C3.
Is there continuity?
YES-Repair short in the wire between the DC-DC converter and the MCM (C3).
NO-Update the MCM If it does not have the latest software, or substitute a known-good MCM, then recheck. If the symptom/indication goes away with a known-good MCM, replace the original MCM.
11. Turn the ignition switch ON (II).





12. Measure voltage between MCM connector terminals C3 and C9.
Is there about 4.5 V?
YES-Go to step 13.
NO-Update the MCM if it does not have the latest software, or substitute a known-good MCM, then recheck. If the symptom/indication goes away with a known-good MCM, replace the original MCM.





13. Measure voltage between DC-DC converter 8P connector terminals No. 7 and No. 8.
Is there about 4.5 V?
YES-Replace the DC-DC converter.
NO-Go to step 14.
14. Turn the ignition switch OFF.





15. Check for continuity between DC-DC converter 8P connector terminal No. 7 and MCM connector terminal C3.
Is there continuity?
YES-Repair open in the wire between the DC-DC converter and the MCM (C9).
NO-Repair open in the wire between the DC-DC converter and the MCM (C3).