diff --git a/IO_Modbus.cpp b/IO_Modbus.cpp
index 888b470..7703442 100644
--- a/IO_Modbus.cpp
+++ b/IO_Modbus.cpp
@@ -527,16 +527,16 @@ void Modbus::_loop(unsigned long currentMicros) {
 
   uint8_t error;
   error = modbusmaster->writeMultipleHoldingRegisters(_currentNode->getNodeID(), 0, _currentNode->holdingRegisters, _currentNode->getNumHoldingRegisters());
-  if (error != 0) DIAG(F("ModbusHR: %02d %04d %04d %s"), _currentNode->getNodeID(), 0, _currentNode->getNumHoldingRegisters(), errorStrings[error]);
+  if (error != 0) DIAG(F("ModbusHR: %02d %04d %04d %s"), _currentNode->getNodeID(), 0, _currentNode->getNumHoldingRegisters(), &errorStrings[error]);
 
   error = modbusmaster->writeMultipleCoils(_currentNode->getNodeID(), 0, _currentNode->coils, _currentNode->getNumCoils());
-  if (error != 0) DIAG(F("ModbusMC: %02d %04d %04d %s"), _currentNode->getNodeID(), 0, _currentNode->getNumCoils(), errorStrings[error]);
+  if (error != 0) DIAG(F("ModbusMC: %02d %04d %04d %s"), _currentNode->getNodeID(), 0, _currentNode->getNumCoils(), &errorStrings[error]);
 
   error = modbusmaster->readDiscreteInputs(_currentNode->getNodeID(), 0, _currentNode->discreteInputs, _currentNode->getNumDisInputs());
-  if (error != 0) DIAG(F("ModbusDI: %02d %04d %04d %s"), _currentNode->getNodeID(), 0, _currentNode->getNumDisInputs(), errorStrings[error]);
+  if (error != 0) DIAG(F("ModbusDI: %02d %04d %04d %s"), _currentNode->getNodeID(), 0, _currentNode->getNumDisInputs(), &errorStrings[error]);
 
   error = modbusmaster->readInputRegisters(_currentNode->getNodeID(), 0, _currentNode->inputRegisters, _currentNode->getNumInputRegisters());
-  if (error != 0) DIAG(F("ModbusIR: %02d %04d %04d %s"), _currentNode->getNodeID(), 0, _currentNode->getNumInputRegisters(), errorStrings[error]);
+  if (error != 0) DIAG(F("ModbusIR: %02d %04d %04d %s"), _currentNode->getNodeID(), 0, _currentNode->getNumInputRegisters(), &errorStrings[error]);
 }
 
 // Link to chain of CMRI bus instances