diff --git a/src/Access/RelationshipFieldAccess.php b/src/Access/RelationshipFieldAccess.php
index 3e9622a..eefb7f0 100644
--- a/src/Access/RelationshipFieldAccess.php
+++ b/src/Access/RelationshipFieldAccess.php
@@ -3,6 +3,7 @@
 namespace Drupal\jsonapi\Access;
 
 use Drupal\Core\Access\AccessResult;
+use Drupal\Core\Access\AccessResultReasonInterface;
 use Drupal\Core\Entity\FieldableEntityInterface;
 use Drupal\Core\Routing\Access\AccessInterface;
 use Drupal\Core\Session\AccountInterface;
@@ -40,15 +41,18 @@ class RelationshipFieldAccess implements AccessInterface {
    */
   public function access(Request $request, Route $route, AccountInterface $account) {
     $relationship_field_name = $route->getRequirement(static::ROUTE_REQUIREMENT_KEY);
-    $is_mutation_request = in_array($request->getMethod(), ['POST', 'PATCH', 'DELETE']);
-    $field_operation = $is_mutation_request ? 'edit' : 'view';
-    $entity_operation = $is_mutation_request ? 'update' : 'view';
-    if ($resource_type = Routes::getResourceTypeNameFromParameters($route->getDefaults())) {
+    $field_operation = $request->isMethodSafe() ? 'view' : 'edit';
+    $entity_operation = $request->isMethodSafe() ? 'view' : 'update';
+    if ($resource_type = $request->get(Routes::RESOURCE_TYPE_KEY)) {
       $entity = $request->get($resource_type->getEntityTypeId());
       if ($entity instanceof FieldableEntityInterface && $entity->hasField($relationship_field_name)) {
         $entity_access = $entity->access($entity_operation, $account, TRUE);
         $field_access = $entity->get($relationship_field_name)->access($field_operation, $account, TRUE);
-        return $entity_access->andIf($field_access);
+        $access_result = $entity_access->andIf($field_access);
+        if ($access_result instanceof AccessResultReasonInterface) {
+          $access_result->setReason("The current user is not allowed to $field_operation this relationship. " . $access_result->getReason());
+        }
+        return $access_result;
       }
     }
     return AccessResult::neutral();
diff --git a/src/Controller/EntityResource.php b/src/Controller/EntityResource.php
index b76b201..2d6235b 100644
--- a/src/Controller/EntityResource.php
+++ b/src/Controller/EntityResource.php
@@ -383,7 +383,7 @@ class EntityResource {
   /**
    * Gets the related resource.
    *
-   * @param \Drupal\Core\Entity\EntityInterface $entity
+   * @param \Drupal\Core\Entity\FieldableEntityInterface $entity
    *   The requested entity.
    * @param string $related_field
    *   The related field name.
@@ -393,12 +393,9 @@ class EntityResource {
    * @return \Drupal\jsonapi\ResourceResponse
    *   The response.
    */
-  public function getRelated(EntityInterface $entity, $related_field, Request $request) {
-    $related_field = $this->resourceType->getInternalName($related_field);
-    $this->relationshipAccess($entity, 'view', $related_field);
+  public function getRelated(FieldableEntityInterface $entity, $related_field, Request $request) {
     /* @var \Drupal\Core\Field\EntityReferenceFieldItemListInterface $field_list */
-    $field_list = $entity->get($related_field);
-    $this->validateReferencedResource($field_list, $related_field);
+    $field_list = $entity->get($this->resourceType->getInternalName($related_field));
     // Add the cacheable metadata from the host entity.
     $cacheable_metadata = CacheableMetadata::createFromObject($entity);
     $is_multiple = $field_list
@@ -446,7 +443,7 @@ class EntityResource {
   /**
    * Gets the relationship of an entity.
    *
-   * @param \Drupal\Core\Entity\EntityInterface $entity
+   * @param \Drupal\Core\Entity\FieldableEntityInterface $entity
    *   The requested entity.
    * @param string $related_field
    *   The related field name.
@@ -458,41 +455,13 @@ class EntityResource {
    * @return \Drupal\jsonapi\ResourceResponse
    *   The response.
    */
-  public function getRelationship(EntityInterface $entity, $related_field, Request $request, $response_code = 200) {
-    $related_field = $this->resourceType->getInternalName($related_field);
-    $this->relationshipAccess($entity, 'view', $related_field);
+  public function getRelationship(FieldableEntityInterface $entity, $related_field, Request $request, $response_code = 200) {
     /* @var \Drupal\Core\Field\FieldItemListInterface $field_list */
-    $field_list = $entity->get($related_field);
-    $this->validateReferencedResource($field_list, $related_field);
+    $field_list = $entity->get($this->resourceType->getInternalName($related_field));
     $response = $this->buildWrappedResponse($field_list, $response_code);
     return $response;
   }
 
-  /**
-   * Validates that the referenced field points to an enabled resource.
-   *
-   * @param \Drupal\Core\Field\EntityReferenceFieldItemListInterface|null $field_list
-   *   The field list with the reference.
-   * @param string $related_field
-   *   The internal name of the related field.
-   *
-   * @throws \Symfony\Component\HttpKernel\Exception\NotFoundHttpException
-   *   If the field is not a reference or the target resource is disabled.
-   * @throws \Symfony\Component\HttpKernel\Exception\HttpException
-   *   If the $field_list is of the incorrect type.
-   */
-  protected function validateReferencedResource($field_list, $related_field) {
-    if (
-      !is_null($field_list) &&
-      !$field_list instanceof EntityReferenceFieldItemListInterface
-    ) {
-      throw new HttpException(500, 'Invalid internal structure for relationship field list.');
-    }
-    if (!$field_list || !$this->isRelationshipField($field_list)) {
-      throw new NotFoundHttpException(sprintf('The relationship %s is not present in this resource.', $related_field));
-    }
-  }
-
   /**
    * Adds a relationship to a to-many relationship.
    *
@@ -518,7 +487,6 @@ class EntityResource {
   public function createRelationship(EntityInterface $entity, $related_field, $parsed_field_list, Request $request) {
     $related_field = $this->resourceType->getInternalName($related_field);
     /* @var \Drupal\Core\Field\EntityReferenceFieldItemListInterface $parsed_field_list */
-    $this->relationshipAccess($entity, 'update', $related_field);
     if ($parsed_field_list instanceof Response) {
       // This usually means that there was an error, so there is no point on
       // processing further.
@@ -619,7 +587,6 @@ class EntityResource {
       return $parsed_field_list;
     }
     /* @var \Drupal\Core\Field\EntityReferenceFieldItemListInterface $parsed_field_list */
-    $this->relationshipAccess($entity, 'update', $related_field);
     // According to the specification, PATCH works a little bit different if the
     // relationship is to-one or to-many.
     /* @var \Drupal\Core\Field\EntityReferenceFieldItemListInterface $field_list */
@@ -708,8 +675,6 @@ class EntityResource {
       throw new BadRequestHttpException(sprintf('You need to provide a body for DELETE operations on a relationship (%s).', $related_field));
     }
     /* @var \Drupal\Core\Field\EntityReferenceFieldItemListInterface $parsed_field_list */
-    $this->relationshipAccess($entity, 'update', $related_field);
-
     $field_name = $parsed_field_list->getName();
     $field_access = $parsed_field_list->access('edit', NULL, TRUE);
     if (!$field_access->isAllowed()) {
diff --git a/tests/src/Functional/ResourceResponseTestTrait.php b/tests/src/Functional/ResourceResponseTestTrait.php
index f9e74b7..d5e1cd3 100644
--- a/tests/src/Functional/ResourceResponseTestTrait.php
+++ b/tests/src/Functional/ResourceResponseTestTrait.php
@@ -465,8 +465,9 @@ trait ResourceResponseTestTrait {
    *   for testing related/relationship routes and includes.
    * @param string|null $detail
    *   (optional) Details for the JSON API error object.
-   * @param string|null $pointer
-   *   (optional) Document pointer for the JSON API error object.
+   * @param string|bool|null $pointer
+   *   (optional) Document pointer for the JSON API error object. FALSE to omit
+   *   the pointer.
    * @param string|null $id
    *   (optional) ID for the JSON API error object.
    *
@@ -493,7 +494,7 @@ trait ResourceResponseTestTrait {
     if (!is_null($id)) {
       $error['id'] = $id;
     }
-    if ($relationship_field_name || $pointer) {
+    if ($pointer || $pointer !== FALSE && $relationship_field_name) {
       $error['source']['pointer'] = ($pointer) ? $pointer : $relationship_field_name;
     }
     return (new ResourceResponse(['errors' => [$error]], 403))->addCacheableDependency($access);
diff --git a/tests/src/Functional/ResourceTestBase.php b/tests/src/Functional/ResourceTestBase.php
index 79d7730..2f62ad6 100644
--- a/tests/src/Functional/ResourceTestBase.php
+++ b/tests/src/Functional/ResourceTestBase.php
@@ -1415,9 +1415,8 @@ abstract class ResourceTestBase extends BrowserTestBase {
     $relationship_field_name = 'field_jsonapi_test_entity_ref';
     /* @var \Drupal\Core\Access\AccessResultReasonInterface $update_access */
     $update_access = static::entityAccess($resource, 'update', $this->account)
-      ->andIf(static::entityFieldAccess($resource, $relationship_field_name, 'update', $this->account));
-    $url = Url::fromRoute(sprintf("jsonapi.{$resource_identifier['type']}.relationship"), [
-      'related' => $relationship_field_name,
+      ->andIf(static::entityFieldAccess($resource, $relationship_field_name, 'edit', $this->account));
+    $url = Url::fromRoute(sprintf("jsonapi.{$resource_identifier['type']}.{$relationship_field_name}.relationship"), [
       $resource->getEntityTypeId() => $resource->uuid(),
     ]);
 
@@ -1571,13 +1570,13 @@ abstract class ResourceTestBase extends BrowserTestBase {
     else {
       $request_options[RequestOptions::BODY] = Json::encode(['data' => [$target_identifier]]);
       $response = $this->request('POST', $url, $request_options);
-      $message = 'The current user is not allowed to update this relationship.';
+      $message = 'The current user is not allowed to edit this relationship.';
       $message .= ($reason = $update_access->getReason()) ? ' ' . $reason : '';
-      $this->assertResourceErrorResponse(403, $message, $response, $relationship_field_name);
+      $this->assertResourceErrorResponse(403, $message, $response);
       $response = $this->request('PATCH', $url, $request_options);
-      $this->assertResourceErrorResponse(403, $message, $response, $relationship_field_name);
+      $this->assertResourceErrorResponse(403, $message, $response);
       $response = $this->request('DELETE', $url, $request_options);
-      $this->assertResourceErrorResponse(403, $message, $response, $relationship_field_name);
+      $this->assertResourceErrorResponse(403, $message, $response);
     }
 
     // Remove the test entities that were created.
@@ -1600,7 +1599,7 @@ abstract class ResourceTestBase extends BrowserTestBase {
     $entity = $entity ?: $this->entity;
     $access = static::entityFieldAccess($entity, $relationship_field_name, 'view', $this->account);
     if (!$access->isAllowed()) {
-      return static::getAccessDeniedResponse($this->entity, $access, $relationship_field_name, 'The current user is not allowed to view this relationship.');
+      return static::getAccessDeniedResponse($this->entity, $access, $relationship_field_name, 'The current user is not allowed to view this relationship.', FALSE);
     }
     $expected_document = $this->getExpectedGetRelationshipDocument($relationship_field_name);
     $status_code = isset($expected_document['errors'][0]['status']) ? $expected_document['errors'][0]['status'] : 200;
@@ -1719,9 +1718,6 @@ abstract class ResourceTestBase extends BrowserTestBase {
               ],
               'code' => 0,
               'id' => '/' . $base_resource_identifier['type'] . '/' . $base_resource_identifier['id'],
-              'source' => [
-                'pointer' => $relationship_field_name,
-              ],
             ],
           ],
         ], 403))->addCacheableDependency($access);
@@ -2762,7 +2758,7 @@ abstract class ResourceTestBase extends BrowserTestBase {
    *   The AccessResult.
    */
   protected static function entityFieldAccess(EntityInterface $entity, $field_name, $operation, AccountInterface $account) {
-    $entity_access = static::entityAccess($entity, $operation, $account);
+    $entity_access = static::entityAccess($entity, $operation === 'edit' ? 'update' : 'view', $account);
     $field_access = $entity->{$field_name}->access($operation, $account, TRUE);
     return $entity_access->andIf($field_access);
   }