diff --git a/goldens/public-api/router/errors.md b/goldens/public-api/router/errors.md
index 3620d512a5f..ee4961e8c8a 100644
--- a/goldens/public-api/router/errors.md
+++ b/goldens/public-api/router/errors.md
@@ -13,9 +13,7 @@ export const enum RuntimeErrorCode {
     // (undocumented)
     INVALID_DOUBLE_DOTS = 4005,
     // (undocumented)
-    INVALID_GUARD = 4014,
-    // (undocumented)
-    INVALID_ROUTE_CONFIG = 4015,
+    INVALID_ROUTE_CONFIG = 4014,
     // (undocumented)
     MISPLACED_OUTLETS_COMMAND = 4004,
     // (undocumented)
diff --git a/packages/router/src/errors.ts b/packages/router/src/errors.ts
index 5147c9141ae..a8c95998ebc 100644
--- a/packages/router/src/errors.ts
+++ b/packages/router/src/errors.ts
@@ -24,6 +24,5 @@ export const enum RuntimeErrorCode {
   UNEXPECTED_VALUE_IN_URL = 4011,
   OUTLET_NOT_ACTIVATED = 4012,
   OUTLET_ALREADY_ACTIVATED = 4013,
-  INVALID_GUARD = 4014,
-  INVALID_ROUTE_CONFIG = 4015,
+  INVALID_ROUTE_CONFIG = 4014,
 }
diff --git a/packages/router/src/operators/check_guards.ts b/packages/router/src/operators/check_guards.ts
index 1f96585bbfe..5c24f4f47ec 100644
--- a/packages/router/src/operators/check_guards.ts
+++ b/packages/router/src/operators/check_guards.ts
@@ -6,13 +6,12 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {EnvironmentInjector, Injector, ɵRuntimeError as RuntimeError} from '@angular/core';
+import {EnvironmentInjector, Injector} from '@angular/core';
 import {concat, defer, from, MonoTypeOperatorFunction, Observable, of, OperatorFunction, pipe} from 'rxjs';
-import {concatMap, filter, first, map, mergeMap, tap} from 'rxjs/operators';
+import {concatMap, first, map, mergeMap, tap} from 'rxjs/operators';
 
-import {RuntimeErrorCode} from '../errors';
 import {ActivationStart, ChildActivationStart, Event} from '../events';
-import {CanActivateChildFn, CanActivateFn, CanDeactivateFn, CanLoadFn, CanMatch, CanMatchFn, Route} from '../models';
+import {CanLoad, CanLoadFn, CanMatch, CanMatchFn, Route} from '../models';
 import {NavigationTransition} from '../router';
 import {ActivatedRouteSnapshot, RouterStateSnapshot} from '../router_state';
 import {navigationCancelingError, REDIRECTING_CANCELLATION_REASON} from '../shared';
@@ -23,8 +22,6 @@ import {isBoolean, isCanActivate, isCanActivateChild, isCanDeactivate, isCanLoad
 
 import {prioritizedGuardValue} from './prioritized_guard_value';
 
-const NG_DEV_MODE = typeof ngDevMode === 'undefined' || !!ngDevMode;
-
 export function checkGuards(moduleInjector: Injector, forwardEvent?: (evt: Event) => void):
     MonoTypeOperatorFunction<NavigationTransition> {
   return mergeMap(t => {
@@ -117,16 +114,9 @@ function runCanActivate(
   const canActivateObservables = canActivate.map((c: any) => {
     return defer(() => {
       const guard = getToken(c, futureARS, moduleInjector);
-      let observable;
-      if (isCanActivate(guard)) {
-        observable = wrapIntoObservable(guard.canActivate(futureARS, futureRSS));
-      } else if (isFunction<CanActivateFn>(guard)) {
-        observable = wrapIntoObservable(guard(futureARS, futureRSS));
-      } else {
-        throw new RuntimeError(
-            RuntimeErrorCode.INVALID_GUARD, NG_DEV_MODE && 'Invalid CanActivate guard');
-      }
-      return observable.pipe(first());
+      const guardVal = isCanActivate(guard) ? guard.canActivate(futureARS, futureRSS) :
+                                              guard(futureARS, futureRSS);
+      return wrapIntoObservable(guardVal).pipe(first());
     });
   });
   return of(canActivateObservables).pipe(prioritizedGuardValue());
@@ -146,16 +136,9 @@ function runCanActivateChild(
     return defer(() => {
       const guardsMapped = d.guards.map((c: any) => {
         const guard = getToken(c, d.node, moduleInjector);
-        let observable;
-        if (isCanActivateChild(guard)) {
-          observable = wrapIntoObservable(guard.canActivateChild(futureARS, futureRSS));
-        } else if (isFunction<CanActivateChildFn>(guard)) {
-          observable = wrapIntoObservable(guard(futureARS, futureRSS));
-        } else {
-          throw new RuntimeError(
-              RuntimeErrorCode.INVALID_GUARD, NG_DEV_MODE && 'Invalid CanActivateChild guard');
-        }
-        return observable.pipe(first());
+        const guardVal = isCanActivateChild(guard) ? guard.canActivateChild(futureARS, futureRSS) :
+                                                     guard(futureARS, futureRSS);
+        return wrapIntoObservable(guardVal).pipe(first());
       });
       return of(guardsMapped).pipe(prioritizedGuardValue());
     });
@@ -170,16 +153,10 @@ function runCanDeactivate(
   if (!canDeactivate || canDeactivate.length === 0) return of(true);
   const canDeactivateObservables = canDeactivate.map((c: any) => {
     const guard = getToken(c, currARS, moduleInjector);
-    let observable;
-    if (isCanDeactivate(guard)) {
-      observable = wrapIntoObservable(guard.canDeactivate(component!, currARS, currRSS, futureRSS));
-    } else if (isFunction<CanDeactivateFn<any>>(guard)) {
-      observable = wrapIntoObservable(guard(component, currARS, currRSS, futureRSS));
-    } else {
-      throw new RuntimeError(
-          RuntimeErrorCode.INVALID_GUARD, NG_DEV_MODE && 'Invalid CanDeactivate guard');
-    }
-    return observable.pipe(first());
+    const guardVal = isCanDeactivate(guard) ?
+        guard.canDeactivate(component!, currARS, currRSS, futureRSS) :
+        guard(component, currARS, currRSS, futureRSS);
+    return wrapIntoObservable(guardVal).pipe(first());
   });
   return of(canDeactivateObservables).pipe(prioritizedGuardValue());
 }
@@ -193,16 +170,8 @@ export function runCanLoadGuards(
   }
 
   const canLoadObservables = canLoad.map((injectionToken: any) => {
-    const guard = injector.get(injectionToken);
-    let guardVal;
-    if (isCanLoad(guard)) {
-      guardVal = guard.canLoad(route, segments);
-    } else if (isFunction<CanLoadFn>(guard)) {
-      guardVal = guard(route, segments);
-    } else {
-      throw new RuntimeError(
-          RuntimeErrorCode.INVALID_GUARD, NG_DEV_MODE && 'Invalid CanLoad guard');
-    }
+    const guard = injector.get<CanLoad|CanLoadFn>(injectionToken);
+    const guardVal = isCanLoad(guard) ? guard.canLoad(route, segments) : guard(route, segments);
     return wrapIntoObservable(guardVal);
   });