TM 10-3930-675-20-1 0015 00-2 ELECTRONIC CONTROL UNIT (ECU) SUPPLY VOLTAGE TROUBLESHOOTING - CONTINUED 0015 00 Table 2. Error Code 452 - Voltage Supply Too Low for Steering ECU (792) Troubleshooting Procedures. MALFUNCTION TEST OR INSPECTION CORRECTIVE ACTION Error Code 452 - Voltage Supply Too Low for Steering ECU (792) 1.  Remove  cab  circuit  breaker panel and ensure that circuit breakers F26 and F29 are not tripped. Reset     circuit     breaker(s)     as required (WP 0073 00). 2.  Perform    voltage    check    at slave receptacle. Input voltage should be 22-26V. If voltage is present, but below 18V, perform the following: a. Check condition and voltage   of   batteries   (WP 0025 00). a.  Charge or replace batteries as required (WP 0107 00). b. Check condition of alternator    and    alternator drive belt (WP 0069 00 and WP 0070 00). b. Replace alternator  or  tighten or replace alternator drive belt (WP 0069 00 or WP 0070 00). c. Check    charging    rate    of alternator   at   either   slave receptacle, with lights on. c.  If  alternator  is  not  charging properly,   replace   alternator (WP 0069 00). 3.  Check voltage at ECU (792) connector pin 1 and pin 5. If voltage is present, notify SRA. 4.  Check  voltage  at  connector X174 pin 14. If voltage is present, notify SRA to replace wire A17414. 5.  Check  voltage  at  connector X47 pin 8. If voltage is present, notify SRA to replace wire 478. 6.  Check  voltage  at  connector X174 pin 3. If voltage is present, notify SRA to replace wire A1743A. 7.  Check  voltage  at  connector X47 pin 3. If voltage is present, notify SRA to replace wire 473. Table 3. Error Code 811 - Voltage Supply Too Low for Transmission ECU (793) Troubleshooting Procedures. MALFUNCTION TEST OR INSPECTION CORRECTIVE ACTION Error  Code 811  -  Voltage Supply Too Low for Transmission ECU (793) 1.  Remove  cab  circuit  breaker panel and ensure that circuit breakers F27 and F28 are not tripped. Reset     circuit     breaker(s)     as required (WP 0073 00).