diff --git a/browser/components/search/test/browser_bing.js b/browser/components/search/test/browser_bing.js
index 6327036e11dd..592f5cfddc70 100644
--- a/browser/components/search/test/browser_bing.js
+++ b/browser/components/search/test/browser_bing.js
@@ -18,7 +18,7 @@ function test() {
 
   // Test search URLs (including purposes).
   url = engine.getSubmission("foo").uri.spec;
-  is(url, base, "Check search URL for 'foo'");
+  is(url, base + "&form=MOZSBR", "Check search URL for 'foo'");
   url = engine.getSubmission("foo", null, "contextmenu").uri.spec;
   is(url, base + "&form=MOZCON", "Check context menu search URL for 'foo'");
   url = engine.getSubmission("foo", null, "keyword").uri.spec;
@@ -39,7 +39,7 @@ function test() {
     name: "Bing",
     alias: null,
     description: "Bing. Search by Microsoft.",
-    searchForm: "https://www.bing.com/search?q=&pc=MOZI",
+    searchForm: "https://www.bing.com/search?q=&pc=MOZI&form=MOZSBR",
     hidden: false,
     wrappedJSObject: {
       queryCharset: "UTF-8",
diff --git a/browser/components/search/test/browser_bing_behavior.js b/browser/components/search/test/browser_bing_behavior.js
index 1ea6a9d401b6..bc9b187ec0e8 100644
--- a/browser/components/search/test/browser_bing_behavior.js
+++ b/browser/components/search/test/browser_bing_behavior.js
@@ -23,7 +23,7 @@ function test() {
 
   // Test search URLs (including purposes).
   url = engine.getSubmission("foo").uri.spec;
-  is(url, base, "Check search URL for 'foo'");
+  is(url, base + "&form=MOZSBR", "Check search URL for 'foo'");
 
   waitForExplicitFinish();
 
diff --git a/browser/components/search/test/browser_yahoo.js b/browser/components/search/test/browser_yahoo.js
index 8d5ec501b490..f45b47d0cc9b 100644
--- a/browser/components/search/test/browser_yahoo.js
+++ b/browser/components/search/test/browser_yahoo.js
@@ -18,7 +18,21 @@ function test() {
 
   // Test search URLs (including purposes).
   url = engine.getSubmission("foo").uri.spec;
-  is(url, base, "Check search URL for 'foo'");
+  is(url, base + "&hsimp=yhs-001", "Check search URL for 'foo'");
+  url = engine.getSubmission("foo", null, "searchbar").uri.spec;
+  is(url, base + "&hsimp=yhs-001", "Check search bar search URL for 'foo'");
+  url = engine.getSubmission("foo", null, "keyword").uri.spec;
+  is(url, base + "&hsimp=yhs-002", "Check keyword search URL for 'foo'");
+  url = engine.getSubmission("foo", null, "homepage").uri.spec;
+  is(url, base + "&hsimp=yhs-003", "Check homepage search URL for 'foo'");
+  url = engine.getSubmission("foo", null, "newtab").uri.spec;
+  is(url, base + "&hsimp=yhs-004", "Check newtab search URL for 'foo'");
+  url = engine.getSubmission("foo", null, "contextmenu").uri.spec;
+  is(url, base + "&hsimp=yhs-005", "Check context menu search URL for 'foo'");
+  url = engine.getSubmission("foo", null, "system").uri.spec;
+  is(url, base + "&hsimp=yhs-007", "Check system search URL for 'foo'");
+  url = engine.getSubmission("foo", null, "invalid").uri.spec;
+  is(url, base + "&hsimp=yhs-001", "Check invalid URL for 'foo'");
 
   // Check search suggestion URL.
   url = engine.getSubmission("foo", "application/x-suggestions+json").uri.spec;
@@ -29,7 +43,7 @@ function test() {
     name: "Yahoo",
     alias: null,
     description: "Yahoo Search",
-    searchForm: "https://search.yahoo.com/yhs/search?p=&ei=UTF-8&hspart=mozilla",
+    searchForm: "https://search.yahoo.com/yhs/search?p=&ei=UTF-8&hspart=mozilla&hsimp=yhs-001",
     hidden: false,
     wrappedJSObject: {
       queryCharset: "UTF-8",
diff --git a/browser/components/search/test/browser_yahoo_behavior.js b/browser/components/search/test/browser_yahoo_behavior.js
index f8206df8f5fe..5b2d61422d2e 100644
--- a/browser/components/search/test/browser_yahoo_behavior.js
+++ b/browser/components/search/test/browser_yahoo_behavior.js
@@ -23,7 +23,7 @@ function test() {
 
   // Test search URLs (including purposes).
   url = engine.getSubmission("foo").uri.spec;
-  is(url, base, "Check search URL for 'foo'");
+  is(url, base + "&hsimp=yhs-001", "Check search URL for 'foo'");
 
   waitForExplicitFinish();
 
diff --git a/browser/locales/en-US/searchplugins/google.xml b/browser/locales/en-US/searchplugins/google.xml
index 742bdcf588ea..0642d56f94c0 100644
--- a/browser/locales/en-US/searchplugins/google.xml
+++ b/browser/locales/en-US/searchplugins/google.xml
@@ -12,7 +12,7 @@
   <Param name="q" value="{searchTerms}"/>
   <Param name="ie" value="utf-8"/>
   <Param name="oe" value="utf-8"/>
-  <Param name="client" value="firefox-b"/>
   <MozParam name="client" condition="purpose" purpose="keyword" value="firefox-b-ab"/>
+  <MozParam name="client" condition="purpose" purpose="searchbar" value="firefox-b"/>
 </Url>
 </SearchPlugin>
diff --git a/toolkit/components/search/nsSearchService.js b/toolkit/components/search/nsSearchService.js
index 4a79b0aa205d..b1d411b8001c 100644
--- a/toolkit/components/search/nsSearchService.js
+++ b/toolkit/components/search/nsSearchService.js
@@ -1138,12 +1138,11 @@ EngineURL.prototype = {
 
   getSubmission: function SRCH_EURL_getSubmission(aSearchTerms, aEngine, aPurpose) {
     var url = ParamSubstitution(this.template, aSearchTerms, aEngine);
-    // Default to an empty string if the purpose is not provided so that default purpose params
-    // (purpose="") work consistently rather than having to define "null" and "" purposes.
-    var purpose = aPurpose || "";
+    // Default to searchbar if the purpose is not provided
+    var purpose = aPurpose || "searchbar";
 
-    // If the 'system' purpose isn't defined in the plugin, fallback to 'searchbar'.
-    if (purpose == "system" && !this.params.some(p => p.purpose == "system"))
+    // If a particular purpose isn't defined in the plugin, fallback to 'searchbar'.
+    if (!this.params.some(p => p.purpose !== undefined && p.purpose == purpose))
       purpose = "searchbar";
 
     // Create an application/x-www-form-urlencoded representation of our params
diff --git a/toolkit/components/search/tests/xpcshell/data/engine.xml b/toolkit/components/search/tests/xpcshell/data/engine.xml
index 699f952eb238..e7af1d9e9ed4 100644
--- a/toolkit/components/search/tests/xpcshell/data/engine.xml
+++ b/toolkit/components/search/tests/xpcshell/data/engine.xml
@@ -16,8 +16,8 @@
 </Url>
 <Url type="application/x-moz-default-purpose" method="GET" template="http://www.google.com/search" resultdomain="purpose.google.com">
   <Param name="q" value="{searchTerms}"/>
-  <!-- MozParam with a default value if purpose is not specified -->
-  <MozParam name="channel" condition="purpose" purpose="" value="none"/>
+  <!-- MozParam uses searchbar if purpose is not specified -->
+  <MozParam name="channel" condition="purpose" purpose="searchbar" value="ffsb"/>
   <MozParam name="channel" condition="purpose" purpose="contextmenu" value="rcs"/>
   <MozParam name="channel" condition="purpose" purpose="keyword" value="fflb"/>
 </Url>
diff --git a/toolkit/components/search/tests/xpcshell/test_purpose.js b/toolkit/components/search/tests/xpcshell/test_purpose.js
index c49052d59bcc..46465e0a3c89 100644
--- a/toolkit/components/search/tests/xpcshell/test_purpose.js
+++ b/toolkit/components/search/tests/xpcshell/test_purpose.js
@@ -43,12 +43,13 @@ add_task(function* test_purpose() {
 
   // Tests for a param that varies with a purpose but has a default value.
   base = "http://www.google.com/search?q=foo";
-  check_submission("&channel=none", "foo", "application/x-moz-default-purpose");
-  check_submission("&channel=none", "foo", "application/x-moz-default-purpose", null);
-  check_submission("&channel=none", "foo", "application/x-moz-default-purpose", "");
+  check_submission("&channel=ffsb", "foo", "application/x-moz-default-purpose");
+  check_submission("&channel=ffsb", "foo", "application/x-moz-default-purpose", null);
+  check_submission("&channel=ffsb", "foo", "application/x-moz-default-purpose", "");
   check_submission("&channel=rcs",  "foo", "application/x-moz-default-purpose", "contextmenu");
   check_submission("&channel=fflb", "foo", "application/x-moz-default-purpose", "keyword");
-  check_submission("",              "foo", "application/x-moz-default-purpose", "invalid");
+  check_submission("&channel=ffsb", "foo", "application/x-moz-default-purpose", "searchbar");
+  check_submission("&channel=ffsb", "foo", "application/x-moz-default-purpose", "invalid");
 
   // Tests for a purpose on the search form (ie. empty query).
   engine = Services.search.getEngineByName("engine-rel-searchform-purpose");