diff --git a/build.out b/build.out
index eefcc8a..50bf30d 100644
--- a/build.out
+++ b/build.out
@@ -1 +1 @@
-{"builds":[{"imageName":"gcr.io/lesser-weevil/emailservice","tag":"gcr.io/lesser-weevil/emailservice:v0.1.0-33-g6e6db3b@sha256:593de0cc94b95fa033838a3d3f3dc0168cc35f736b01ace2954b3648771e1027"},{"imageName":"gcr.io/lesser-weevil/productcatalogservice","tag":"gcr.io/lesser-weevil/productcatalogservice:v0.1.0-33-g6e6db3b@sha256:29dc89ac7aa66dcb70fd1c9e84f422a5e0c4bcb117ed0cb29c7cd6282ab13bbe"},{"imageName":"gcr.io/lesser-weevil/recommendationservice","tag":"gcr.io/lesser-weevil/recommendationservice:v0.1.0-33-g6e6db3b@sha256:de6cddba59ea40a879baf25b2ae58dd06b64532d0ca52dda4c4b6d22e577f0d6"},{"imageName":"gcr.io/lesser-weevil/shippingservice","tag":"gcr.io/lesser-weevil/shippingservice:v0.1.0-33-g6e6db3b@sha256:0ee734d45b10760c0d01bf3ca27a85b56296337adfe540f344860b2de1eb0277"},{"imageName":"gcr.io/lesser-weevil/checkoutservice","tag":"gcr.io/lesser-weevil/checkoutservice:v0.1.0-33-g6e6db3b@sha256:d9b7a695508b8df8d894d4b1ea24ebc8f651c069daab64df4acb2556c72ace1d"},{"imageName":"gcr.io/lesser-weevil/paymentservice","tag":"gcr.io/lesser-weevil/paymentservice:v0.1.0-33-g6e6db3b@sha256:93d422fe681b9ac2aed353b5b22f447dcd305bb297980edb0dfd68719e9dde65"},{"imageName":"gcr.io/lesser-weevil/currencyservice","tag":"gcr.io/lesser-weevil/currencyservice:v0.1.0-33-g6e6db3b@sha256:5dd9f85c65b0ab000f759ea37d78ff06643ea800220e9e34c251f3c1e33ab2b9"},{"imageName":"gcr.io/lesser-weevil/cartservice","tag":"gcr.io/lesser-weevil/cartservice:v0.1.0-33-g6e6db3b@sha256:6cc3baab0bdf2eda1ec9da076a102007c851a665c9fd8ee99d741c734c8a85fe"},{"imageName":"gcr.io/lesser-weevil/frontend","tag":"gcr.io/lesser-weevil/frontend:v0.1.0-33-g6e6db3b@sha256:43d6cbbfb02cb9a4435063c63127f1f4e22a8954f38cc78159c1ae7e44700bdd"},{"imageName":"gcr.io/lesser-weevil/loadgenerator","tag":"gcr.io/lesser-weevil/loadgenerator:v0.1.0-33-g6e6db3b@sha256:88ece337b51771e0a10cc09d8db31dd474d93fcbc47b145a9d9f6a27e24a5fb4"},{"imageName":"gcr.io/lesser-weevil/adservice","tag":"gcr.io/lesser-weevil/adservice:v0.1.0-33-g6e6db3b@sha256:dcb2c1644648b9c18c6fc48ad7fc1a15f4dc890ad3fca531b9892d6cfdf1a305"}]}
\ No newline at end of file
+{"builds":[{"imageName":"gcr.io/lesser-weevil/emailservice","tag":"gcr.io/lesser-weevil/emailservice:v0.1.0-43-ga32631d@sha256:593de0cc94b95fa033838a3d3f3dc0168cc35f736b01ace2954b3648771e1027"},{"imageName":"gcr.io/lesser-weevil/productcatalogservice","tag":"gcr.io/lesser-weevil/productcatalogservice:v0.1.0-43-ga32631d@sha256:29dc89ac7aa66dcb70fd1c9e84f422a5e0c4bcb117ed0cb29c7cd6282ab13bbe"},{"imageName":"gcr.io/lesser-weevil/recommendationservice","tag":"gcr.io/lesser-weevil/recommendationservice:v0.1.0-43-ga32631d@sha256:de6cddba59ea40a879baf25b2ae58dd06b64532d0ca52dda4c4b6d22e577f0d6"},{"imageName":"gcr.io/lesser-weevil/shippingservice","tag":"gcr.io/lesser-weevil/shippingservice:v0.1.0-43-ga32631d@sha256:0ee734d45b10760c0d01bf3ca27a85b56296337adfe540f344860b2de1eb0277"},{"imageName":"gcr.io/lesser-weevil/checkoutservice","tag":"gcr.io/lesser-weevil/checkoutservice:v0.1.0-43-ga32631d@sha256:d9b7a695508b8df8d894d4b1ea24ebc8f651c069daab64df4acb2556c72ace1d"},{"imageName":"gcr.io/lesser-weevil/paymentservice","tag":"gcr.io/lesser-weevil/paymentservice:v0.1.0-43-ga32631d-dirty@sha256:4df214a8153671eef258d9329054f2fb21eb6331d2a4b475a731d115ec16e33c"},{"imageName":"gcr.io/lesser-weevil/currencyservice","tag":"gcr.io/lesser-weevil/currencyservice:v0.1.0-43-ga32631d@sha256:7de984152d48e33d3b02f001dceb6d97f504478ac27c33dcaa27cb981c445e88"},{"imageName":"gcr.io/lesser-weevil/cartservice","tag":"gcr.io/lesser-weevil/cartservice:v0.1.0-43-ga32631d@sha256:6cc3baab0bdf2eda1ec9da076a102007c851a665c9fd8ee99d741c734c8a85fe"},{"imageName":"gcr.io/lesser-weevil/frontend","tag":"gcr.io/lesser-weevil/frontend:v0.1.0-43-ga32631d@sha256:43d6cbbfb02cb9a4435063c63127f1f4e22a8954f38cc78159c1ae7e44700bdd"},{"imageName":"gcr.io/lesser-weevil/loadgenerator","tag":"gcr.io/lesser-weevil/loadgenerator:v0.1.0-43-ga32631d-dirty@sha256:15a1adb67f03da4ef24ced791737413db372fb8eccfcc9b8155b9e1205903a97"},{"imageName":"gcr.io/lesser-weevil/adservice","tag":"gcr.io/lesser-weevil/adservice:v0.1.0-43-ga32631d@sha256:dcb2c1644648b9c18c6fc48ad7fc1a15f4dc890ad3fca531b9892d6cfdf1a305"}]}
\ No newline at end of file
diff --git a/src/loadgenerator/locustfile.py b/src/loadgenerator/locustfile.py
index eb81322..2167799 100644
--- a/src/loadgenerator/locustfile.py
+++ b/src/loadgenerator/locustfile.py
@@ -59,6 +59,10 @@ def addToCart(l):
 
 def checkout(l):
     addToCart(l)
+    # For five minutes every other hour, credit cards passed by the user will be
+    # invalid and the paymentservice will fail.
+    now = time.localtime()
+    expiration_year = '2015' if (now.tm_hour % 2) & (now.tm_min < 5) else '2060'
     l.client.post("/cart/checkout", {
         'email': 'someone@example.com',
         'street_address': '1600 Amphitheatre Parkway',
@@ -68,7 +72,7 @@ def checkout(l):
         'country': 'United States',
         'credit_card_number': '4432-8015-6152-0454',
         'credit_card_expiration_month': '1',
-        'credit_card_expiration_year': '2039',
+        'credit_card_expiration_year': expiration_year,
         'credit_card_cvv': '672',
     })
 
diff --git a/src/paymentservice/charge.js b/src/paymentservice/charge.js
index ce9674a..fe7b9da 100644
--- a/src/paymentservice/charge.js
+++ b/src/paymentservice/charge.js
@@ -15,6 +15,7 @@
 const cardValidator = require('simple-card-validator');
 const uuid = require('uuid/v4');
 const pino = require('pino');
+const grpc = require('grpc');
 
 const logger = pino({
   name: 'paymentservice-charge',
@@ -28,6 +29,7 @@ class CreditCardError extends Error {
   constructor (message) {
     super(message);
     this.code = 400; // Invalid argument error
+    this.status = grpc.status.INVALID_ARGUMENT;
   }
 }