diff --git a/lib/errors/errordefinitions.js b/lib/errors/errordefinitions.js
index 877be20..8a7bdbd 100644
--- a/lib/errors/errordefinitions.js
+++ b/lib/errors/errordefinitions.js
@@ -21,11 +21,13 @@ var errors = {
   TX_CANNOT_CREATE: 'Cannot create TX proposal during backoff time',
   TX_CANNOT_REMOVE: 'Cannot remove this tx proposal during locktime',
   TX_NOT_ACCEPTED: 'The transaction proposal is not accepted',
+  TX_NOT_FOUND: 'Transaction proposal not found',
   TX_NOT_PENDING: 'The transaction proposal is not pending',
   UPGRADE_NEEDED: 'Client app needs to be upgraded',
   WALLET_ALREADY_EXISTS: 'Wallet already exists',
   WALLET_FULL: 'Wallet full',
-  WALLET_NOT_COMPLETE: 'Replace only works on complete wallets',
+  WALLET_NOT_COMPLETE: 'Wallet is not complete',
+  WALLET_NOT_FOUND: 'Wallet not found',
 };
 
 var errorObjects = _.zipObject(_.map(errors, function(msg, code) {
diff --git a/lib/server.js b/lib/server.js
index 9f6da6f..0bb93b4 100644
--- a/lib/server.js
+++ b/lib/server.js
@@ -253,7 +253,7 @@ WalletService.prototype.getWallet = function(opts, cb) {
 
   self.storage.fetchWallet(self.walletId, function(err, wallet) {
     if (err) return cb(err);
-    if (!wallet) return cb(new ClientError('Wallet not found'));
+    if (!wallet) return cb(Errors.WALLET_NOT_FOUND);
     return cb(null, wallet);
   });
 };
@@ -285,7 +285,7 @@ WalletService.prototype.replaceTemporaryRequestKey = function(opts, cb) {
     self.storage.fetchWallet(self.walletId, function(err, wallet) {
       if (err) return cb(err);
 
-      if (!wallet) return cb(new ClientError('Wallet not found'));
+      if (!wallet) return cb(Errors.WALLET_NOT_FOUND);
       var hash = WalletUtils.getCopayerHash(opts.name, opts.xPubKey, opts.requestPubKey);
       if (!self._verifySignature(hash, opts.copayerSignature, wallet.pubKey)) {
         return cb(new ClientError());
@@ -397,7 +397,7 @@ WalletService.prototype.joinWallet = function(opts, cb) {
     self.storage.fetchWallet(opts.walletId, function(err, wallet) {
 
       if (err) return cb(err);
-      if (!wallet) return cb(new ClientError('Wallet not found'));
+      if (!wallet) return cb(Errors.WALLET_NOT_FOUND);
 
       var hash = WalletUtils.getCopayerHash(opts.name, opts.xPubKey, opts.requestPubKey);
       if (!self._verifySignature(hash, opts.copayerSignature, wallet.pubKey)) {
@@ -544,8 +544,7 @@ WalletService.prototype.createAddress = function(opts, cb) {
   self._runLocked(cb, function(cb) {
     self.getWallet({}, function(err, wallet) {
       if (err) return cb(err);
-      if (!wallet.isComplete())
-        return cb(new ClientError('Wallet is not complete'));
+      if (!wallet.isComplete()) return cb(Errors.WALLET_NOT_COMPLETE);
 
       var address = wallet.createAddress(false);
 
@@ -977,8 +976,7 @@ WalletService.prototype.createTx = function(opts, cb) {
   self._runLocked(cb, function(cb) {
     self.getWallet({}, function(err, wallet) {
       if (err) return cb(err);
-      if (!wallet.isComplete())
-        return cb(new ClientError('Wallet is not complete'));
+      if (!wallet.isComplete()) return cb(Errors.WALLET_NOT_COMPLETE);
 
       var copayer = wallet.getCopayer(self.copayerId);
       var hash;
@@ -1087,7 +1085,7 @@ WalletService.prototype.getTx = function(opts, cb) {
 
   self.storage.fetchTx(self.walletId, opts.txProposalId, function(err, txp) {
     if (err) return cb(err);
-    if (!txp) return cb(new ClientError('Transaction proposal not found'));
+    if (!txp) return cb(Errors.TX_NOT_FOUND);
     return cb(null, txp);
   });
 };
@@ -1665,7 +1663,7 @@ WalletService.prototype.scan = function(opts, cb) {
   self._runLocked(cb, function(cb) {
     self.getWallet({}, function(err, wallet) {
       if (err) return cb(err);
-      if (!wallet.isComplete()) return cb(new ClientError('Wallet is not complete'));
+      if (!wallet.isComplete()) return cb(Errors.WALLET_NOT_COMPLETE);
 
       wallet.scanStatus = 'running';
       self.storage.storeWallet(wallet, function(err) {
@@ -1724,7 +1722,7 @@ WalletService.prototype.startScan = function(opts, cb) {
 
   self.getWallet({}, function(err, wallet) {
     if (err) return cb(err);
-    if (!wallet.isComplete()) return cb(new ClientError('Wallet is not complete'));
+    if (!wallet.isComplete()) return cb(Errors.WALLET_NOT_COMPLETE);
 
     setTimeout(function() {
       self.scan(opts, scanFinished);
diff --git a/test/integration/server.js b/test/integration/server.js
index 4b5e217..cb19bf0 100644
--- a/test/integration/server.js
+++ b/test/integration/server.js
@@ -1547,7 +1547,8 @@ describe('Wallet service', function() {
             server.createAddress({}, function(err, address) {
               should.not.exist(address);
               should.exist(err);
-              err.message.should.contain('not complete');
+              err.code.should.equal('WALLET_NOT_COMPLETE');
+              err.message.should.equal('Wallet is not complete');
               done();
             });
           });
@@ -1578,7 +1579,7 @@ describe('Wallet service', function() {
             server.createTx(txOpts, function(err, tx) {
               should.not.exist(tx);
               should.exist(err);
-              err.message.should.contain('not complete');
+              err.code.should.equal('WALLET_NOT_COMPLETE');
               done();
             });
           });
@@ -2906,7 +2907,8 @@ describe('Wallet service', function() {
       }, function(err, txp) {
         should.exist(err);
         should.not.exist(txp);
-        err.message.should.contain('not found');
+        err.code.should.equal('TX_NOT_FOUND')
+        err.message.should.equal('Transaction proposal not found');
         done();
       });
     });
@@ -3178,7 +3180,7 @@ describe('Wallet service', function() {
         should.not.exist(err);
         server.getWallet({}, function(err, w) {
           should.exist(err);
-          err.message.should.equal('Wallet not found');
+          err.code.should.equal('WALLET_NOT_FOUND');
           should.not.exist(w);
           async.parallel([
 
@@ -3237,7 +3239,7 @@ describe('Wallet service', function() {
         function(next) {
           server.getWallet({}, function(err, wallet) {
             should.exist(err);
-            err.message.should.contain('not found');
+            err.code.should.equal('WALLET_NOT_FOUND');
             next();
           });
         },