diff --git a/master/fsm_coe.c b/master/fsm_coe.c
index 9e5feaf1..21f3ce23 100644
--- a/master/fsm_coe.c
+++ b/master/fsm_coe.c
@@ -1024,6 +1024,7 @@ void ec_fsm_coe_down_start(ec_fsm_coe_t *fsm /**< finite state machine */)
         ec_print_data(data, 10 + request->data_size);
     }
 
+    fsm->request->jiffies_sent = jiffies;
     fsm->retries = EC_FSM_RETRIES;
     fsm->state = ec_fsm_coe_down_request;
 }
@@ -1052,6 +1053,19 @@ void ec_fsm_coe_down_request(ec_fsm_coe_t *fsm /**< finite state machine */)
     }
 
     if (datagram->working_counter != 1) {
+        if (!datagram->working_counter) {
+            unsigned long diff_ms =
+                (jiffies - fsm->request->jiffies_sent) * 1000 / HZ;
+            if (diff_ms < fsm->request->response_timeout) {
+                if (fsm->slave->master->debug_level) {
+                    EC_DBG("Slave %u did no respond to Sdo download request. "
+                            "Retrying after %u ms...\n",
+                            slave->ring_position, (u32) diff_ms);
+                    // no response; send request datagram again
+                    return;
+                }
+            }
+        }
         fsm->state = ec_fsm_coe_error;
         EC_ERR("Reception of CoE download request failed on slave %u: ",
                 slave->ring_position);
@@ -1253,6 +1267,7 @@ void ec_fsm_coe_up_start(ec_fsm_coe_t *fsm /**< finite state machine */)
         ec_print_data(data, 10);
     }
 
+    fsm->request->jiffies_sent = jiffies;
     fsm->retries = EC_FSM_RETRIES;
     fsm->state = ec_fsm_coe_up_request;
 }
@@ -1281,6 +1296,19 @@ void ec_fsm_coe_up_request(ec_fsm_coe_t *fsm /**< finite state machine */)
     }
 
     if (datagram->working_counter != 1) {
+        if (!datagram->working_counter) {
+            unsigned long diff_ms =
+                (jiffies - fsm->request->jiffies_sent) * 1000 / HZ;
+            if (diff_ms < fsm->request->response_timeout) {
+                if (fsm->slave->master->debug_level) {
+                    EC_DBG("Slave %u did no respond to Sdo upload request. "
+                            "Retrying after %u ms...\n",
+                            slave->ring_position, (u32) diff_ms);
+                    // no response; send request datagram again
+                    return;
+                }
+            }
+        }
         fsm->state = ec_fsm_coe_error;
         EC_ERR("Reception of CoE upload request failed on slave %u: ",
                 slave->ring_position);
diff --git a/master/fsm_coe_map.c b/master/fsm_coe_map.c
index ba3fed2a..3a46020a 100644
--- a/master/fsm_coe_map.c
+++ b/master/fsm_coe_map.c
@@ -44,10 +44,6 @@
 #include "sdo_request.h"
 #include "fsm_coe_map.h"
 
-/** Retry reading the number of assigned Pdos if this time is not elapsed.
- */
-#define EC_FSM_COE_MAP_TIMEOUT 5
-
 /*****************************************************************************/
 
 void ec_fsm_coe_map_state_start(ec_fsm_coe_map_t *);
@@ -186,8 +182,8 @@ void ec_fsm_coe_map_action_next_dir(
         ec_pdo_list_clear_pdos(&fsm->pdos);
 
         ec_sdo_request_address(&fsm->request, fsm->sync_sdo_index, 0);
+        fsm->request.response_timeout = 10000;
         ecrt_sdo_request_read(&fsm->request);
-        fsm->jiffies_start = jiffies;
         fsm->state = ec_fsm_coe_map_state_pdo_count;
         ec_fsm_coe_transfer(fsm->fsm_coe, fsm->slave, &fsm->request);
         ec_fsm_coe_exec(fsm->fsm_coe); // execute immediately
@@ -214,15 +210,6 @@ void ec_fsm_coe_map_state_pdo_count(
     if (ec_fsm_coe_exec(fsm->fsm_coe)) return;
 
     if (!ec_fsm_coe_success(fsm->fsm_coe)) {
-        if (jiffies - fsm->jiffies_start < HZ * EC_FSM_COE_MAP_TIMEOUT) {
-            if (fsm->slave->master->debug_level)
-                EC_DBG("Failed to read number of assigned Pdos from "
-                        "slave %u. Retrying...\n", fsm->slave->ring_position);
-            ecrt_sdo_request_read(&fsm->request);
-            ec_fsm_coe_transfer(fsm->fsm_coe, fsm->slave, &fsm->request);
-            ec_fsm_coe_exec(fsm->fsm_coe); // execute immediately
-            return;
-        }
         EC_ERR("Failed to read number of assigned Pdos from slave %u.\n",
                 fsm->slave->ring_position);
         fsm->state = ec_fsm_coe_map_state_error;
@@ -252,6 +239,7 @@ void ec_fsm_coe_map_action_next_pdo(
     if (fsm->sync_subindex <= fsm->sync_subindices) {
         ec_sdo_request_address(&fsm->request, fsm->sync_sdo_index,
                 fsm->sync_subindex);
+        fsm->request.response_timeout = 0;
         ecrt_sdo_request_read(&fsm->request);
         fsm->state = ec_fsm_coe_map_state_pdo;
         ec_fsm_coe_transfer(fsm->fsm_coe, fsm->slave, &fsm->request);
@@ -309,6 +297,7 @@ void ec_fsm_coe_map_state_pdo(
     list_add_tail(&fsm->pdo->list, &fsm->pdos.list);
 
     ec_sdo_request_address(&fsm->request, fsm->pdo->index, 0);
+    fsm->request.response_timeout = 0;
     ecrt_sdo_request_read(&fsm->request);
     fsm->state = ec_fsm_coe_map_state_pdo_entry_count;
     ec_fsm_coe_transfer(fsm->fsm_coe, fsm->slave, &fsm->request);
@@ -356,6 +345,7 @@ void ec_fsm_coe_map_action_next_pdo_entry(
 {
     if (fsm->pdo_subindex <= fsm->pdo_subindices) {
         ec_sdo_request_address(&fsm->request, fsm->pdo->index, fsm->pdo_subindex);
+        fsm->request.response_timeout = 0;
         ecrt_sdo_request_read(&fsm->request);
         fsm->state = ec_fsm_coe_map_state_pdo_entry;
         ec_fsm_coe_transfer(fsm->fsm_coe, fsm->slave, &fsm->request);
diff --git a/master/fsm_coe_map.h b/master/fsm_coe_map.h
index fb71b879..297fec02 100644
--- a/master/fsm_coe_map.h
+++ b/master/fsm_coe_map.h
@@ -72,8 +72,6 @@ struct ec_fsm_coe_map
     ec_sdo_t *pdo_sdo; /**< Current Pdo Sdo. */
     uint8_t pdo_subindices; /**< Number of Pdo entries. */
     uint16_t pdo_subindex; /**< Current subindex in Pdo Sdo. */
-
-    unsigned long jiffies_start; /**< Timestamp. */
 };
 
 /*****************************************************************************/
diff --git a/master/sdo_request.c b/master/sdo_request.c
index 0e4e8d2d..df2b81b2 100644
--- a/master/sdo_request.c
+++ b/master/sdo_request.c
@@ -70,7 +70,8 @@ void ec_sdo_request_init(
     req->mem_size = 0;
     req->data_size = 0;
     req->dir = EC_DIR_OUTPUT;
-    req->timeout = 0; // no timeout
+    req->issue_timeout = 0; // no timeout
+    req->response_timeout = 0; // immediate response required
     req->state = EC_REQUEST_INIT;
 }
 
@@ -170,8 +171,8 @@ int ec_sdo_request_copy_data(
  */
 int ec_sdo_request_timed_out(const ec_sdo_request_t *req /**< Sdo request. */)
 {
-    return req->timeout
-        && jiffies - req->start_jiffies > HZ * req->timeout / 1000;
+    return req->issue_timeout
+        && jiffies - req->jiffies_start > HZ * req->issue_timeout / 1000;
 }
 
 /*****************************************************************************
@@ -180,7 +181,7 @@ int ec_sdo_request_timed_out(const ec_sdo_request_t *req /**< Sdo request. */)
 
 void ecrt_sdo_request_timeout(ec_sdo_request_t *req, uint32_t timeout)
 {
-    req->timeout = timeout;
+    req->issue_timeout = timeout;
 }
 
 /*****************************************************************************/
@@ -210,7 +211,7 @@ void ecrt_sdo_request_read(ec_sdo_request_t *req)
 {
     req->dir = EC_DIR_INPUT;
     req->state = EC_REQUEST_QUEUED;
-    req->start_jiffies = jiffies;
+    req->jiffies_start = jiffies;
 }
 
 /*****************************************************************************/
@@ -219,7 +220,7 @@ void ecrt_sdo_request_write(ec_sdo_request_t *req)
 {
     req->dir = EC_DIR_OUTPUT;
     req->state = EC_REQUEST_QUEUED;
-    req->start_jiffies = jiffies;
+    req->jiffies_start = jiffies;
 }
 
 /*****************************************************************************/
diff --git a/master/sdo_request.h b/master/sdo_request.h
index 688a04a3..fcf2029b 100644
--- a/master/sdo_request.h
+++ b/master/sdo_request.h
@@ -58,12 +58,17 @@ struct ec_sdo_request {
     uint8_t *data; /**< Pointer to Sdo data. */
     size_t mem_size; /**< Size of Sdo data memory. */
     size_t data_size; /**< Size of Sdo data. */
-    uint32_t timeout; /**< Timeout in ms. */
+    uint32_t issue_timeout; /**< Maximum time in ms, the processing of the
+                              request may take. */
+    uint32_t response_timeout; /**< Maximum time in ms, the transfer is
+                                 retried, if the slave does not respond. */
     ec_direction_t dir; /**< Direction. EC_DIR_OUTPUT means downloading to
                           the slave, EC_DIR_INPUT means uploading from the
                           slave. */
     ec_request_state_t state; /**< Sdo request state. */
-    unsigned long start_jiffies; /**< Jiffies, when the request was issued. */
+    unsigned long jiffies_start; /**< Jiffies, when the request was issued. */
+    unsigned long jiffies_sent; /**< Jiffies, when the upload/download
+                                     request was sent. */
 };
 
 /*****************************************************************************/